Algebra Textbook for Younger Students

[mathmarm]

1 hour ago, square_25 said:

I have never, ever gotten good results out of teaching a formula first and then explaining it to kids. I've experimented with this at AoPS -- if you start with the formula, you run a much higher chance of someone treating something like a black box they not only will not understand, but will not really feel motivated to understand.

I'm not super-worried about this. The thing about teaching 1-1 day in and day out, is that I can do both to whatever degree is needed, simultaneously.

I'm not about to pretend I've never presented a formula first, then worked on the derivation of it. I've done it dozens of times.

No, I can't quite put my finger on what it is about Ch.6 that's bothering me. But it's not strictly their approach to the QF.

 

[mathmarm]

21 hours ago, square_25 said:

 I would also want to spend time on absolute value aside from square roots, as it's a concept and requires internalizing. Same with properties of radicals -- unless your son is already fluent with the properties of radicals,

I only gave a rough over-view of Ch6, but keep in mind that I'm talking about the sixth chapter in this text.
In the text, Exponents are taught in Ch-1, Absolute value in Ch 2-2,  and Radicals are tuaght in Ch 5. So the students will have seen and worked with AV and radicals before being reminded of it in Ch6.
By the time that they see these things in Ch 6, students are recalling and extending something that they've already been exposed to and practiced.

In Ch6 they formalize the AV concept with a more precise definition and use radicals it in a way that will tie in with students ability to understand its use in the derivation of the QF by chapters end.

From what I've seen, the text has already introduced, explained and practiced the student with the prerequisite skills.

The book is well written and conceptually sturdy. It's scope and sequence might not be 100% perfect according to me, but it's a strong text or I wouldn't have ever bought it and I certainly wouldn't have started it with my Big Boy if it wasn't "good enough" for him 🙂

[mathmarm]

28 minutes ago, square_25 said:

Sorry, I’m just trying to go off of what you wrote — I don’t know the book!! I don’t know what is bugging you about the chapter, so I’m just taking shots in the dark. If you figure out what it is, I’d be happy to troubleshoot :-).

I was just addressing that particular point, because I know other people will see these messages at some point. I am just writing these notes real time and on the fly, so they aren't coherent or comprehensive but since I'm making them public, I need to address (potential) concerns as they are raised or it won't be a good review of the book for others reference.

However, you are fine so don't apologize so much.

 

 

[mathmarm]

We're only a few days in, but I"m so happy with our book choice thus far. Jr is still enthusiastic about it, which is very important.

Jr. loves to write and is loving having a real math book. These are his math notes for the last 3 lessons. Algebra 1 CH1 - JR_2.pdf
I'm going to ignore the doodle (which he knows definitely isn't supposed to be in this book 🙁 when he has tons of drawing papers).

For now our approach of buddy reading and discussing with a board near by is working. He's loving having to write the math notes--that might be his favorite part. I only allow him to write a few. For 1-6, I assigned 4, but he snuck in some extra because he wanted to.

So far, we buddy read and discuss the lesson, then we answer all of the lesson problems, but we discuss them and he does them orally. Today he asked that we not orally answer the problems he's going to write before he writes them. So moving forward we will give that a try.

 

 

[mathmarm]

39 minutes ago, square_25 said:

What are you guys working on now, by the way? 🙂

He's loving everything about using the math book on the couch, then making notes.  I think that aside from giving him more "writing homework" it feels very "big kid" to him, He's asked for "writing homework" several times in the past but even though I gave him some, we've always kept his writing "homework" to a minimum. We want him to write in his own time but I guess making up something to write is a struggle for him still? He draws much more freely than he writes.

I'm torn between letting him go at his pace vs pacing him.

I think I will be stricter with pacing the rate at which he writes for Chapter 2.

Outside of the book, we have other math strands that we practice regularly. I'm going to introduce and begin teaching some set theory soonish.

[mathmarm]

WHOOPS NEVER MIND!

Edited April 2, 2020 by mathmarm
Nevermind! I was wrong, wrong, wrong!

[mathmarm]

Ok! So I grabbed the book and looked again after posting my previous post and I was super wrong .

If you saw what the other post used to say, please ignore it.

I checked the book and Chapter 6 Forester Algebra 1 includes plenty of discussion worthy problems. Some kind of way, I was just missing them!

[mathmarm]

1 minute ago, square_25 said:

 

Hah, then I won't continue with the list I was typing!

By all means, please do!

Edited April 2, 2020 by mathmarm

[mathmarm]

4 hours ago, square_25 said:

 

Good thing I still had it copied, lol!  😄

 

Is any of this interesting at all to you? I'd love some guidance about what kinds of questions you like! 

Yes, keep going.

We've got a whiteboard going about finding zeros of a functions. It's an exploration that grew out of our daily graphing activities.

[mathmarm]

4 hours ago, square_25 said:

I'd love some guidance about what kinds of questions you like! 

Questions that prompt a second-look or a deeper look at a concept. They don't have to be super-difficult questions--in fact, I don't want them to be hard questions, just thoughtful questions.

Questions that--when you think about and discuss them, they help you flesh out your understanding of a topic or they help you realize something else.

For example, in the lesson that introduces integers (2-1) there are the questions:

(32) Adding a negative number to another number is the same what other operation.
(33) What is meant by
- a negative number,  
- an integer, 
-a real number?

In 2-3 (subtracting signed numbers) they have the practice problems where you simply tell if the parenthesis are needed in each case as a part of the oral drill.
This is an intelligent exercise that I've not seen in many remedial or even college algebra textbooks. The thoughtfulness of the exercises inclusion is impressive, because I've had tons of students who never know if they're supposed to use parenthesis or not.

In 2-4 (multipltication of signed numbers) these are 2 of the questions:
(51) From the answers to Problems 47-50, you can see that -x and -1*x always stand for the same number. True or false: Does the expression -x always stand for a negative number? Explain.
(52) Explain the difference in meaning between -x^2 and (-x)^2.

 

All of these questions are simple, but thoughtfully included. Rather than just can you compute this it's inviting thought. It's requiring the student to pause, reflect on what they've been doing to pick up on something that they may or may not have even noticed in the first place.

Edited April 3, 2020 by mathmarm

[mathmarm]

In lesson 3-3 they have:
(63) Tell the difference between an axiom and any other property.

In 5-2 they introduce a formal definition of polynomials have:
(57) The expression 7 / (x-5) is not a polynomial, since it involves division by an expression containing a variable.
For what value of x is the expression not equal to a real number? Explain.

These are not hard questions. But they encourage thoughtfulness.Their inclusion in the text helps me remember any points that I might want to make. Some of these questions are obviously designed to even preempt students from making bad turns and ending up in common pitfalls that students find themselves in.

I like to collect these types of thinking questions, because it could be the sort of thing that I might take for granted or forget to ask, but by asking and exploring it a few times with Jr. I'm able to help him grow or reinforce his understanding of the concept.

[mathmarm]

I think it's going to work best if we do book-math earlier in the day than later. That way, it serves as is a nice transition to the table work for our school day.

If we do the math book lesson on the couch right after morning meeting then when he goes to do his notes for, we'll segue right to the table work when he's done. Hes finished all of his table-school for the day and it's not even 12 yet.

🙂

 

 

 

 

[mathmarm]

So, 1-7 is the lesson where you solve equations and Jr knows the concept very well, and he enjoyed reading through  and discussing that lesson again. He really seemed to like the way the book illustrated the concept very simply with scales. He's very familiar with the number-balance so I guess he just enjoyed seeing that same concept in a book?

However, he hit a road block with the last part of the exercises. Where the equations have a fraction as the coefficient of x.

At first he said he couldn't do it. Then we talked some about what fraction notation tells us. We looked at the problems he had already done with ease.

Because of the way that he was first introduced to fraction notation as symbol for division he had no problem with and easily understood that with equations like: (1/3)x = 4, he had to multiply by 3. But when the equations took the form (2/3)x = 6, he got confused for a moment.

We used the whiteboard, factored those types of fractions into a form that he could easily "see" and did a few examples.

He was finally able to tell me that (2/3)x means that x is multiplied by 2 and divided by 3. We did a few examples on the board, then he was able to do the first 2 practice problems from the textbook. Algebra 1 CH1 - JR_3.pdf

However, when we discussed the problems afterwards he mentioned that you have to divide first! 🤯

So, we spent the next day looking at more of these equations--factoring and commuting the fractional coefficients and discussing the problems.
When we had 3 examples on the board--both of them done 2-ways--I asked him to tell me what he noticed, he explained to me that since you factor, and multiplication is commutative, it doesn't matter if you divide first or not when removing the fractional coefficient. Whew!

Finally, he used his notebook time solving the rest of the practice problems in this lesson. Algebra 1 CH1 - JR_4.pdf

Today, we move on to 1-8, but I will keep these fractional equations in the rotation for a little while.

Edited April 5, 2020 by mathmarm

[mathmarm]

That was a nice little jolt to remind me that just because he's getting the individual problems "right" doesn't mean that he he is getting the underlying concept "right".

It's so important to keep the dialogue going so that misunderstandings like this are taught and dealt with promptly.

[mathmarm]

So, I've been thinking a lot about algorithms in arithmetic or algebra.

@square_25 I could probably guess what you're going to say, but what do you think? Is there a right time to insist on the use of an algorithm? If so, when?

Jr is very fluent with manipulating numbers. He understands the arithmetic operations and the basic properties. He has methods of performing each of the operations, but there is no sure-fire pattern to how he solves various problems.  Mostly, he uses the distributive property to perform multiplication or division, but sometimes he does the "ink-saving" way (which is just a form of the standard algorithm). He uses integers to subtract as often as he regroups. He does mental math or finger-abacus to add/subtract a lot.

He has a mix of strategies that he uses. He understands the operations and he is really clever with numbers, but should I insist on an algorithm at a certain point? If so, when?

 

[mathmarm]

@square_25 Jr, "discovered" reciprocals.

We've been working a few fractional equations each day since last week and I've been discussing with him about the equations.
2 days before Yesterday, he generalized that: whenever there is a fraction you just have to undo the multiplication and the division.
A day before yesterday I asked him about that insight again and as we worked on a few problems he said "Division and multiplication are the same level, so you could actually do them both at the same time."

When I pushed him on that idea some more he seemed confused so I backed off of it. Yesterday we reviewed what he'd come up with so far and continued to work a few problems, I coach him to keep using his words and I kept using his words from the last couple of days as we worked through the problems.

Today he told me that we can use multiplication by another fraction--"the opposite fraction"--  to clear the fraction in one move. I pushed back on that language (he knows integers and that -3 and 3 are "opposites") so we discussed what it would mean for a fraction to be oppostie and after that rabbit hole, he agreed that it's wrong to call it an opposite fraction and changed the wording to "the inverting fraction".

We did several equations with the "inverting fraction" shortcut.

 

[mathmarm]

1 minute ago, square_25 said:

Neat!! How did he figure out to multiply by the reciprocal? (Does he think of it as the reciprocal, that is, as 1/f, where f is the original fraction?)

As a mathematician, I’d say that both are reasonable definitions of “opposites” — they are just inverses for different operations! 😉

Can you clarify what you mean by "how did he figure out to multiply by the reciprocal"?
From what he's told me, thus far, he hasn't mentioned that the reciprocal is 1/f, where f is the original fraction. We haven't done work with complex fractions in a while, so I personally really doubt that he's noticed that or would make that leap.

It could be semantics, but I really disagree that it's okay to call 1/3 the opposite of 3. Each number can only have a single opposite.

I understand his thinking and instinct for the language-choice--it isn't unreasonable to dub it "opposite fraction"--but, it is wrong.

If 3/4 is the opposite (-3/4), it can't be the opposite of (4/3) too.
 But, I acknowledge that I much prefer precision and consistency in mathematical language.

[mathmarm]

  

3 hours ago, square_25 said:

I guess I don’t really think “opposite” is proper mathematical terminology, anyway — I think you’d want to use “negative” and “reciprocal” for that.

Point. However "opposite" is a widely-used, well-understood term in mathematics in the US.
In the US the term "opposite" is used to mean the "additive inverse" of a number. In my experience, I have never--not once--seen "Opposite"  used for the multiplicative inverse--we only call that the "reciprocal" or "multiplicative inverse"

More importantly, Jr. already knows the concept of "opposite" as most (US educated) students know it-- as a word that is compatible only with "Additive inverse".
I'll teach him the word "reciprocal" soon enough and pretty soon we'll get to to the terms additive-inverse and multiplicative-inverse anyway but my experience has taught me that it's always best to nip "sloppy" in the bud quickly.

3 hours ago, square_25 said:

Sounds like he’s having fun with the book!! I’m glad :-). I love the updates!! Thank you for writing them up.

I think he is. I've slowed him down. I want to preserve the enjoyment of the written book-work,I want the activity to fit within a certain time-slot and it leaves more time for other threads 🙂

6 hours ago, square_25 said:

Neat!! Does he think of it as multiplying by 1/f, where f is the original fraction?

Or do you mean he figured out to undo multiplication by a/b by multiplying by b/a, but not necessarily that one is 1 over the other? Either way, that’s a lovely insight!!

As a mathematician, I’d say that both are reasonable definitions of “opposites” — they are just inverses for different operations! 😉

He has not summarized the reciprocal in terms of complex fractions at all and it's been a good long while since he's done any real complex fractions so I doubt that he's made that connection yet. But, he does know complex fractions fairly well, so he might have that little nugget rolling around in his brain somewhere, just waiting for him to unearth it. 🤷🏿‍♀️

[mathmarm]

9 hours ago, square_25 said:

a- mathematician versus not mathematician disconnect (as I said, I've done math only in English since I was 11, which was a while ago) --
b-I've really never seen any math contest people or mathematicians use the terminology this way.

c-I just asked my mathematician DH, who was born in Boston and is certainly US educated, what the opposite of 3 was, and he actually said 1/3 :-P. He said he'd never heard anyone use that wording for negatives, either.

 

d-But I'd probably gently move to "negative" and "reciprocal" for clarity in higher math. Or additive and multiplicative inverse! Those work, too 🙂.

a- School math vs math is an excellent point. The word "opposite" is firmly in the school-math vernacular in the US.
NOTE: I specify US, not because you're European, but because I thought I remembered you saying that you went to school in Canada at 11.
So while it's uber-common for US-educated 11-14 year olds to be expected to learn, understand and know the word "opposite" for the additive-inverse, I can't say what they do in Canada.
I really doubt that "opposite" is a universally an English-math word because I have had Anglophone students from other countries who learned integers as "directed numbers" and with other terminology. But I do expect that US-educated students in that age-range would learn and know the word "opposite"

b-That's curious. I know that "opposite" is used in BA5 and AoPS Prealgebra, so I'd be really curious to poll 5th-9th grade students in math clubs to see if they really just don't know the term of if the formality of being in a math contest/club means that they are inclined/encouraged to use "proper" math terms only.

The concept of the additive inverse is often introduced by the label of "opposite".    -7 is the opposite of 7 and 8.4 is the opposite of -8.4
The concept of the multiplicative inverse is often introduced under the label of "reciprocal" 4/7 is the reciprocal of 7/4 and 5 is the reciprocal.

c-No, I think your DH simply made a mistake. In the realm of school-math--at least in the US--saying that 1/3 is the opposite of 3 is wrong.
It's possible  that he never learned the term, but I think it's  more likely that he's long since forgotten the word--since it is dropped early on in most Algebra 1 classes--but if he was educated in the US and is speaking the expected math-vernacular then he is wrong to say that 1/3 is the opposite for 3.

d-I want him to have the "expected understanding" of reciprocal and opposite before I transition to using additive-inverse and multiplicative-inverse a little more exclusively.

[mathmarm]

11 hours ago, square_25 said:

E-By complex fractions, do you mean things like 2/3 as opposed to 1 over something? We're definitely still working on fraction arithmetic around here, alongside of algebra -- DD gets it and can do it, but she isn't automatic about it, and she occasionally has trouble taking her knowledge and applying it to situations with variables (I asked her to figure out general formulas for the sum, difference, product and quotient of a/b and c/d, and I think it took an hour, even though she can do it numerically quite quickly.) Fractions are tricky!! 

F-We seem to be solidly in "how to write a proof" around here. DD7 is suddenly writing tons and tons of proofs -- sometimes, she's using words where she really should just write down the sequence of algebraic manipulations :-P. We've been working on solving equations by completing the square and graphing a few lines (although for now, I only have her plot some points.) I'm not entirely sure how long we'll stay in this "early algebra" phase -- G- I need to go back and teach her long division and about lowest common multiples and greatest common factors and some geometry and whatnot! 

E-Complex fractions are just fractions, within fractions. Like these here.

F-I really look forward to when Jr. begins writing proofs, we're not there yet, but I think he'll take to it ok when we start.
Like you daughter, he's very confident with the numerical-only, but he talks his way through everything with variables. He can verbally explain the process to me fluidly, and talk me through the process, and gives the justifications verbally (and informally) but I don't think he can do it himself while he's solving the problem.

G-I don't think your DD will need to go over long-division for long. Do you have an approach for long-division that you want to use with her, or are you open to suggestions?

I have found that many kids find "long division" easier after using the distributive property for a while (some kids take a long time, some kids take a short time). Jr transitioned  to the "Standard" algorithm for long division quite easily after doing "long division" with the distributive property for a bit.

We

Edited April 9, 2020 by mathmarm

[mathmarm]

12 minutes ago, square_25 said:

 

Yeah, I have no idea. He just didn't know what it meant and that was the first thing that came into his head. I actually didn't know he'd say 1/3: I was curious what he'd say and whether he knew this terminology. We don't have BA5 and I've never taught AoPS Prealgebra online (I probably should, for experience and to get some teaching ideas!), so I can't comment on that. I really had no idea this phrasing was so prevalent. 

If you're only working with students in Algebra and beyond, then you could easily miss the usage of "opposite" Many Algebra 1 texts introduce more formal terminology fairly early on.

[mathmarm]

4 minutes ago, square_25 said:

Oh, I see what you mean about complex fractions!! We do use those once in a while, but not super often, either.

Proofs are fun! We had some sort of leap where they became much easier for her. We weren’t doing them 3 months ago!!

I’m not worried about long division. She’s currently basically doing it in expanded form (finding the number of 100s, then 10s then 1s.) For a while, she was resistant to doing that even though she used the distributive property to multiply, and that’s why we didn’t cover the algorithm for it yet. I think she’ll learn the algorithm in a day or two at her current level of preparation: that’s how long the other standard algorithms took. But I do need to go back and cover it, because she’s suuuuper slow dividing in expanded form right now!!

Jr. was crazy about complex fractions at one point. When he was learning to do pen and paper math, he went through a phase where he really liked to do long calculations for all sorts of "scary looking" expressions. When he demonstrated consistency and mastery with the skills, I backed him off of so much calculation because I want to make sure his math education stays balanced. I backed him down to 2 calculations a day. Just enough to maintain the skill, but he wasn't missing any of them so I refocused him on other math-things and it's been a while since he's asked for one.

I can't lie. I'm tempted to start a move towards proofs, but since math isn't our main focus for school, I will save his writing stamina/academic energy for the "main subjects". I know that Chapter 3 of the textbook we have introduces proofs and I already have plans to revisit the main part of Ch3 at the end of this year. So for now, I'll just teach vicariously through you.

Yes, the algorithms take a day or two when the student is well-prepared with the concepts. So I wouldn't make going back for the long-division algorithm a priority.
If she's slow, then I would just work on building up her fluency with the expanding. Would you please share a sample of how your DD does long division currently?

 

[mathmarm]

6 minutes ago, square_25 said:

I want long division for repeating decimals and the factor theorem, anyway :-). I’m not in a rush, but it naturally comes next.

She solves a multiplication equation right now. She needs to do some estimating instead just going up by 100 each time, lol, but otherwise it’s fine. She’s started estimating now (my picture is from more than a week ago), so I’d actually say long division is on the near horizon as a low hanging fruit. 

Very interesting approach. Though now I'm curious why you're subordinating the arithmetic, to the algebraic.

Did you make the conscious decision to go in this order? (I'd love to hear your rationale if so.)

[mathmarm]

 

30 minutes ago, square_25 said:

I'm not sure what you mean. How am I subordinating the arithmetic to the algebraic? 

I may have misunderstood, but I thought you plan to use the factor theorem to develop the algorithm for long-division with your DD.

I just find this approach of using algebra to explore and build-out a childs understanding of arithmetic fascinating.

[mathmarm]

Oh too bad. It would make a neat experiment, . But Hubby would not be happy with me if I conducted that experiment on the kids.

 

[mathmarm]

So this brings me back around to my question about algorithms.

I'm going to ask Jr to solve the same division problem to show you an illustration of the behavior that I'm seeing in him.

He knows the long division algorithm. Most of his practice with it has been with 1-digit divisors,  but he's had some experience with 2- and 3-digit divisors as well.

[mathmarm]

So, he spent 12 or 15 minutes doing the green page. @square_25

I asked him if he could do it another way. He spent 3 minutes doing the white page.

division_example.pdf

[mathmarm]

While he first learned to divide by using the distributive property on the chunked-up-dividend, I don't know why he doesn't use the "easy way" when it's clear that chunking the dividend will be cumbersome.

I think part of it is that Jr likes "scary looking" problems. So he likes for them to be long. He will dilly-dally making the problem super complicated looking, so that he can finish it and say how he beat that problem.

I'm curious if there is a point when it would be more beneficial to insist on a particular algorithm. 

But he has strong number sense and very good visualization. When he uses the standard division algorithm he hits it on the best factor immediately.

[daijobu]

On 4/8/2020 at 8:00 PM, mathmarm said:

  

Point. However "opposite" is a widely-used, well-understood term in mathematics in the US.
In the US the term "opposite" is used to mean the "additive inverse" of a number. In my experience, I have never--not once--seen "Opposite"  used for the multiplicative inverse--we only call that the "reciprocal" or "multiplicative inverse"

More importantly, Jr. already knows the concept of "opposite" as most (US educated) students know it-- as a word that is compatible only with "Additive inverse".

 

I disagree.  I never used the term "opposite" (except maybe maybe  coloquially) to mean the negation of a number.  We always use additive inverse or the negation or the negative of a number.  If you had ever asked me to state the "opposite" of a number I would have no idea what you mean.  I would stay away from imprecise terms like "opposite" because I think they only serve to hide what is really going on when we mean additive inverse or negation.  

[mathmarm]

9 hours ago, daijobu said:

I disagree.  I never used the term "opposite" (except maybe maybe  coloquially) to mean the negation of a number.  We always use additive inverse or the negation or the negative of a number.  If you had ever asked me to state the "opposite" of a number I would have no idea what you mean.  I would stay away from imprecise terms like "opposite" because I think they only serve to hide what is really going on when we mean additive inverse or negation.  

To clarify: Do you disagree that the term "opposite" is widely used and well-understood in school-math throughout US? Or do you disagree with something else?

Edited April 10, 2020 by mathmarm

[mathmarm]

So @square_25 I've had a change of plans. We're only doing 1 session of math each day with the book, because I prefer to use the second slot for some "on-level" work for him.I've scrapped my original plan to do the Algebra book in 2 short sessions.

Jr said that he likes doing "Couch Math" in part because it's easy and fun. However, I don't want him to zip through so fast that we miss the chance to flesh out and deepen his understanding of the concepts and solidify his mastery of the skills, But I also want to keep each day of "Couch Math" within the range of "winnable".

I spend 15-20 minutes on Couch Math with him each day.

Lesson 1-9 contains 15 word problems for students to solve. He has a little trouble unpacking them and even though we only did a small sample of problems from other sections, I want him to solve every last one of the word problems, so we're doing just 2 of them a day.
I made a "spiral" out of the book to  fill out our Couch Math time by:

• Giving a few 1-7 problems for him to solve orally or on the whiteboard.
• Giving a few 1-8 problems for him to solve orally or on the whiteboard.
• Doing the 1-9 Oral Practice with him each day (I just change the problems, but I follow the format/pattern from the book)
• Written Math work: having him do just 2 problems from 1-9 at a time.

I added in practicing the skills from 1-7 & 1-8 that he finds easier to keep the majority of the session "winnable". He's still got a weeks worth word problems from 1-9 left, so I'm going to move him ahead to chapter 2 (Ch. 2 is on integers. He already knows this material well, but will enjoy the practice.) while he works through the rest of this section a little at a time.

This week went well and we're consistently finishing the whole shebang at a good pace, so I think we can sustain it through next week. But we'll see. Because he'll be writing the answers to the word problems for 1-9, he might not wind up making many notes from the beginning of chapter 2. He knows integers pretty well, but I'll see if he finds anything that he wants to note.

Plan for Next Week is

• Giving a few 2-1 problems for him to solve orally or on the whiteboard.
• Giving a few 2-2/2-3 problems (adding and subtracting integers respectively) for him to solve orally or on the whiteboard.
• Giving a few 2-4/2-5 problems (multiplying and dividing integers respectively) for him to solve orally or on the whiteboard.
• Doing Oral Practices from 1-9 and/or Chapter 2 with him
• Written Math work: 2 word problems from 1-9

By the time he'll be finished with his word problems we'll be about ready to start 2-6. Which is good, because there was some stuff in there that might be worth noting down, but I"ll see what he thinks.

[mathmarm]

So, I have some mixed feelings about using a textbook but one benefit that I'm finding in using a good textbook, is it helps uncover things to revisit now that Jr is older.

Example 1: Jr. has been able to simplify convoluted-looking expressions for a long-while, he has long since internalized the order of operations.

So, because he can "do it already" and continues to exhibit mastery of the skill, it is just the sort of thing that I might neglect to revisit or check up on. But by buddy-reading and discussing the textbook, we've been discussing each of these familiar basic skills again. We have started a conversation about when a grouping symbol is/isn't needed. It possibly wouldn't have come up for a long time or at all. I like having the support of the scope and sequence (with examples and explanations) to help guide our conversations.

One thing that I don't like about the book are some of the "jokes" through out are unkind. Of course, for a 14-16 year old (the age range of the intended audience) the jokes are going to be more appropriate, but for a 6.5 year old, some of them are in poor taste and I'm going to be censoring 1 or 2 of them for sure.

For example, word problems often have pun-centric names in them. Word problems star characters with names such as
Sid Upp,  Tess T. Fye and her sister Clara, Doug Upp, etc. Those are silly, amusing puns that most students will enjoy. Students in the target audience will chuckle, roll their eyes and move on. But there is also an exercise in 2-6, where you read how Iddy Ottic solved a problem and are supposed to explain why what he did is wrong.

Again this wouldn't be discussion worthy for a teenaged student, but I will use whiteout and a pen to change that name because my kid is 6.5 and I don't want Jr. to think that calling someone who makes a mistake Iddy Otic (idiotic) is funny. When you're 6.5 you need to be told and have reinforced for you that name calling is NOT okay.

Since Jr. picked up on the puns the other day so I know he'll be on the look-out for "jokes" in the names. I'll have to come up with a list of fun names to substitute into these problems.

I'm still not really in love with Chapter 6. I haven't come up with the perfect solution there.

 

 

[Gil]

On 4/9/2020 at 4:08 PM, mathmarm said:

So, he spent 12 or 15 minutes doing the green page. @square_25

I asked him if he could do it another way. He spent 3 minutes doing the white page.

division_example.pdf 603.73 kB · 9 downloads

Are you 100% sure that he is fully fluent in the multiplication and subtraction algorithms?

Since you say he's got a grip on the estimation part, then it really shouldn't take 3 minutes to do this problem with the long-division algorithm.

[mathmarm]

Jr. is 100% fluent in the concept and really fluent with the algorithm as well.

He did take a longer-than-I'd-like amount of time with this problem, but he wasn't at his most focused because the babies were distracting him.

I will keep a closer eye on him when he's working, to make sure that he's not being distracted.

[mathmarm]

So, we wound up doing some lite proofs for the exponential properties this week.
As you know, it wasn't my plan or preference to begin proofs just yet. But he was able to work out the property for raising a power to a power, and for dividing exponents. It went pretty well. He was so excited to show his dad what he'd "discovered" afterwards.

It makes me think that he might enjoy the lessons in Ch.3 that are more proof-oriented. He's cruising along nicely in Ch2, even with me slowing him down and spreading things out.

On 4/16/2020 at 6:06 PM, square_25 said:

@mathmarm, want me to post any of our work once we move on to the next thing?

Sure! Post as much as you have time or the energy for.

[Cake and Pi]

On 4/16/2020 at 4:06 PM, square_25 said:

I then asked her to explain how to expand out (x+y)^2 using logic as opposed to pattern-matching and she struggled a bit as well. 

Conceptualizing these kinds of problems is where manipulatives can be so flippin' handy. I know I've said this before, but I absolutely love our Algebra Lab Gear blocks. They have their limitations, but they're fun and useful for what they are. One of the creators has his original stuff, including printable paper versions of the Lab Gear and out-of-print textbooks, free on his website. https://www.mathed.page/

[mathmarm]

6 hours ago, Cake and Pi said:

Conceptualizing these kinds of problems is where manipulatives can be so flippin' handy. I know I've said this before, but I absolutely love our Algebra Lab Gear blocks. They have their limitations, but they're fun and useful for what they are. One of the creators has his original stuff, including printable paper versions of the Lab Gear and out-of-print textbooks, free on his website. https://www.mathed.page/

How do you proceed, when the kid in question doesn't like manipulatives, and/or seems to be going through an anti-visualizations phase?

 

[mathmarm]

On 4/16/2020 at 6:06 PM, square_25 said:

I then asked her to explain how to expand out (x+y)^2 using logic as opposed to pattern-matching and she struggled a bit as well.

Really it does sound like more of an off day, than a snag.

Since your dd doesn't like manipulatives and has an on-again/off-again relationship with visuals, I'm curious what your scaffolding conversation sounded like?
I know that we both agree on the importance of getting the child conversant in talking about the concepts as a part of the teaching.

For the sake of pedagogical science, I asked Jr. to explain a similiar question and he  also stammered at first.
For us, the scaffolding conversation sounded like this: ( I recorded our exploration on my phone, then transcribed it for you)
 

Quote

Me: Explain for me, how expanding (x-y)^2 works, big-boy.
Jr: They can...uhm, it would be like this *does something with his hands then wrote down his response* the answer is going to be like this x^2 - xy - xy + y^2
Me: So, your response is right, that's correct--good job!--now, can you explain why that's the answer?
Jr: I did the problem.
Me: You did. You did a good job too. But now I need you to give me the explanation.
Jr: uhm...it's like this....*he pointed to each part of (x-y)^2, then trace his finger to the corresponding part of the answer* so then you get the answer.
Me: Ok, so tell me how to get x^2 in the answer?
Jr: Because it's x multiplied by x.
Me: Good. But how do you know that it's x multiplied by x?
Jr: *Points to the ^2 from the original problem.*
Me: I see, so there's an exponent. What does that exponent tell you?
Jr: Square the grouped-together part.
Me: Good, so you really know this!
Jr:   : D
Me: Can you be the teacher, while I'm the student? Since you're the teacher, try to explain it to me so that I understand why you have to square the grouped-together part.
Jr: (making a grown up voice) This says, (x-y)^2. Square means to use the base as a factor twice. {this is directly from how he learned exponents}
Me: Oooh, ok. How do you write that, teacher?
Jr: *wrote down* (x-y)^2 = (x-y)(x-y)
Me: Ok, I want to copy it down too. (I wrote it on a note-pad).
Me: Now what do I do teacher?
Jr: The parenthesis has a meaning too. Think about that meaning and it's...
Me: groups?
Jr: No...m-m-m-m..mul....ti...what is it?
Me: Multiplication.
Jr: Yeah mommy! I knew you were smart.
Me:.... : D. Thanks, can you finish explaining it teacher?
Jr: the parenthesis has a meaning here, it tells us to...
Me: Multiply!
Jr: so you multiply each part of this (x-y) by each part of that (x-y)
Me: Okay...but why?
Jr: ...huh?
Me: Why do I need to multiply each part.
Jr: It's the...uhm...because...the next step is to do that.
Me: Ok, so where does that step come from, teacher?
Jr: from the math.
Me: Teacher, I'm confused.
Jr: No you're not mommy!! Stop being like that!
Me: I just want you to explain it, so that it's clear.
Jr: You're not confused!
After a quick talk about why a teacher should never yell at a student, we got back on track. He was much more in-the-zone now.
Jr: I'm going to show you why (x-y)^2 is x^2 -xy - xy + y^2, okay?
Me: OK!
Jr: The exponent says to use the base as a factor...2 times.
Jr wrote: (x-y)(x-y)
Jr: The parenthesis has another job too, it tells us to do the multiplying operation.
Me: ok, I understand that part. How do I do that multiplication?
Jr thought about for a moment, traced his finger over the steps a couple of times, then said
Jr: Ok, so you know how the distributive property will work with addition or subtraction? So we can do multiply like this: (X-y)(x-y) gives Xx - Xy, and then the rest of the distributive property looks this (x-Y)(x-y) gives Yx+Yy
Me: OH! That's right, I see it now teacher.
Jr: you get 4 little parts Xx -Xy -Yx +Yy because of the way that the multiplication distributed over both parts, 2 times.
Me: Does my answer have to look like that?
Jr looked at what I had written on my notepad and thought about it for a moment
Jr: No. Commuting some of the parts can give you a lot of answers that are the same but look different. Xx can look like x^2, Xy and Yx can both be switched because they're being multiplied. and Yy can look like y^2, because y is a factor twice, which means we can use an exponent!
while he was doing this, he looked at the answer he'd given and changed it from: x^2 - xy - xy + y^2, to x^2 -2xy + y^2

So, as you see, he needed significant prompting in order to go back to the basic definitions and properties. But once he did, he was able to walk his way through the explanation.

Jr was able to solve the problem immediately, but getting to the explanation part took a while. Once we got there, he was there.

 

[Gil]

On 4/16/2020 at 6:05 PM, square_25 said:

My kiddo also plays around like this. It's not super dependent on how fluent she is with the algorithm and is more about how willing she is to use the algorithm in the first place. I tend to not push algorithms until she's more or less approximating the algorithm on her own time for that reason.

Plays around like what?
Keep in mind that my comment was specifically about the white sheet of paper, where his steps were *perfect* but @mathmarm reported that it took 3 minutes  for him to find the quotient.

I trust that mm's son has superb number-sense and his math facts rock solid, so I was curious about whatthe hold-up was time-wise.
Being distracted out of the math-problem itself makes sense.

For a child who is fluent in the prerequisites, and supposed to be fluent in the division itself, that problem should've taken 35-50 seconds, not 180.

 

 

[mathmarm]

46 minutes ago, square_25 said:

Yeah, I see this kind of thing often. She can certainly explain this with NUMBERS very quickly (at least if it’s a single use and not two uses of the distributive property), so the problem for me is that she seems to have temporarily stopped thinking of variables as generalizations of numbers. I saw this often in college kids and it’s a red flag for me.

She eventually explained it well with a bit of prompting, but that’s not really what I’m worried about. I think it’s a bit hard to explain what I mean by symbol shuffling, but I know it when I see it!

I’m not giving up on algebra or anything!! I just think we need a numerical interlude, so the properties she works with feel intuitive given the numerical background. I don’t think she has enough experience multiplying lots of numbers, hence the topics I chose!!

So, what would have been the ideal response for her to tell you for (xy)^3 using logic, not pattern-matching?
When you say that you asked she explain it with logic instead of pattern matching, would you explain what you meant?
What leading questions do you ask her?


It seems like plugging in values for x and y can make this problem  more obscure than just using the definition for exponentiation.
For example, if you plug in x = 4, and y = 3, then you get  (4x3)^3 or 12^3 many kids would say 1728. Or they might say it's 64 x 27, but either way they could lose sight of the property/definition that they are supposed to be using. This seems like you run the risk of getting tangled in numbers.

I would really like to know what sort of leading questions you find best to ask in this type of situation? When do you (expect/want) your DD to plug in numbers, to try, versus using definitions, etc?

[mathmarm]

So, I asked Jr to do (PB)^5 and he did it much more quickly than the (x-y)^2 example and without any real issue.

I didn't have an opportunity to ask him a leading question but when I asked him if it were right, he glanced over his work and said "yes"

PB.pdf

[mathmarm]

33 minutes ago, square_25 said:

I want her to use her logical understanding of the operations. I don't mind if she uses logic that only works on integers, but something using the meaning of the operations is key. 

In this case, I'd want her to justify her work using the fact that (ab)c = a(bc) and the fact that ab = ba, and I'd want her to also be able to explain those properties logically. I find that kids can almost always explain better with specific numbers than with a's and b's, although I'm certainly happy to hear explanations with a's and b's. So I'm happy to take the explanation that (ab)c means you take ab copies of c, and that a(bc) means we take a copies of bc, and since each bc contains b copies of c, that's a total of b + b + ... + b copies of c, added up a times, so ab copies of c again!

I can't see how the stepping through this with the associative property is especially useful for this problem.

(xy)^3
(xy)(xy)(xy)
(xyx)(y)(xy)
(xyxy)(xy)
(xyxy)(x)(y)
(xyxyx)(y)
(xyxyxy), All this is legitimate use of the associative property, but it's not particularly useful. If she was going down this path, I'm not surprised that your DD got confused in this "setting it up with the associative property" phase. At this point, you still haven't commuted anything...

I mean, that's 5 lines of associating before you can commute. If you commute throughout this process, it just looks even more cluttered and messy.

Maybe I'm being dense, but ideally what would you have wanted her to write down? I mean that really, what would this solution have looked like in the perfect scenario?

[mathmarm]

So, if you were to jot-down the "ideal" response to the (xy)^3 what is it? I'd really like to see what you feel is an appropriate/ideal response to this? Do you ever use color-coding?
 

 

[Cake and Pi]

10 hours ago, mathmarm said:

How do you proceed, when the kid in question doesn't like manipulatives, and/or seems to be going through an anti-visualizations phase?

Erm, I don't really know. 🤷‍♀️ My one AL who resists using manipulatives is the weakest in these kinds of concepts, and my one who used manipulatives most extensively is strongest in all things math. You can approach math from a verbal standpoint, but I'm not sure its the most efficient way. I'm coming from an engineering (not real math) background, though. Language was always more of a frilly decoration to be added to math in my mind, but I may be limited by my own visually-based thought processes.

I haven't figured out how to help my one kid who doesn't like manipulatives or visualizing, but instead have found it most effective to let him explore concepts in his own way, which takes significantly longer and seems to result in less robust conceptual understanding. Consequently, he'll be getting to algebra at 10-11 vs. my heavy-manipulatives, super-visual kid who did basic algebraic concepts like (x+y)^2 at 5 and AoPS algebra at 7. The two boys have the same cognitive abilities, so I tend to think the difference is largely due to personality factors and learning habits/preferences.

3 hours ago, square_25 said:

She knows the why, she just stopped keeping it in the back of her head when she used the pattern. I think it’s important to learn the difference between “I learned the pattern” and “I can backtrack the pattern to properties I can easily understand.” The former approach is considerably more fragile.

See, and I don't think my DS 8 uses the pattern at all for things that can be visualized. The way he talks when he explains his work, it sounds like commentary on visuals, and he uses his hands to shape ideas in the air.

[mathmarm]

Of course, you know your DD far better than I do,, but it seems like she got confused around this red-part:

1 hour ago, square_25 said:

As for plugging in numbers, I mostly wanted her to slow down when she got (xyy)(xxy)(xy) and realize there's no way this could work. I think that the step of "Am I sure that's right? If I'm not, let's try some numbers!" is really crucial in working out new operations and it also helps you avoid overgeneralizing.

I am not sure what lead to that, or what came after, but to me (with minimal context) it looks like she bungled the associative property. Perhaps she concluded at this point that what she'd been trying was wrong. That's why I asked you what kind of leading questions you asked during this exercise?

At this point, I would' have clarified and affirmed her intent, but pointed out that she'd made a mistake because she picked up an extra factor of x and an extra factor of y.
It might have been helpful to get her to verbalize her intent by asking her which definitions and properties she's going to use?
So if she IDed "associating property and commuting property" then restart the problem.
"Babe, you said you're going to do associating and commuting. Which one do you want to do first?
(if they begin associating in pain-staking step by step fashion, I might interject to ask "what will you get when you finish all the associating?"
if they know I would encourage them to right down what it looks like when all the pain-staking step-by-step associating is done.
If they don't know then I'd say "Oooh, we'll keep going 🙂 Lets find out what it will look like after all the associating is done." and put up with them doing it in pain-staking step by step fashion.

When she was done associating, I might say
"Good job with that. Now, you said you were going to use associating and commuting, you've associated. So what do you have left to do?"
(repeat the same process outlined above for if she begins commuting in pain-staking step-by-step fashion)
 

Once she has completed associating and commuting, and has some form of xxxyyy, I'd ask her to check that she didn't lose or pick up any factors. (because associating and commuting won't change the # of x-factors or y-factors that she has). Then I'd prompt her to think about what she could do with those repeated factors and I'd expect her to get x^3y^3.

 

I found in my classes that it helps if I can get the student to tell me what they are going to do (in their own words) so that I can help them track through whatever it was that they were thinking as they go. Some times they'll set up a plan that is flawed, but if they're in a space where they could learn from that error, then I might let them make it.

Some of my weaker students, I might tell them which definition and/or properties I want them to use. And we talk through what they are doing and why.

By figuring out what they intend to do for a particular exercise, it helps me to emphasize where a students planning is dead-on vs where their execution is faulty or flawed.

I find it helps them to realize that they DO have the right plan because a lot of my students will panic if they approached a problem with confidence only to have it fail. Many of them panic and change from a winning plan. So by affirming their intentions ahead of time, they don't change from a winning plan, to trying random, panicky things. such as that x{x+y} thing that you're daughter gave you.

[mathmarm]

44 minutes ago, square_25 said:

Well, you don't have a choice, lol. You HAVE to use the associative property for this question. How else could you do it?

I agree that it's clunky. I was hoping she basically had the intuition that you can multiply numbers in any order and way you choose, and she clearly doesn't. However, if you're going to be rigorous about it, you have to use the associative property. But I wasn't all that concerned about her justifying it perfectly: the issue was that she really wasn't sure how to manipulate the numbers. I would have probably been fine with her writing down x^3y^3 without any manipulations, to be honest -- it's just that she kept write down outrageous stuff. (I think her first attempt was x^{x+y} y^{x+y}, which really just makes no sense.)

By the way, the reason I say that you need both the properties is that it's simply not true that 

(xy)^3 = x^3 y^3

in non-commutative or non-associative settings. 

I know perfectly well why one must use both properties, for this exercise, but I think highly granular applications (step-by-step in a painstaking fashion) can open the door for error. It seems like your daughter went off the rails, then floundered writing all sorts of senseless stuff.

Feeling confident about an approach, only to have it end in error can make one a student feel doubtful and unsure.

That's why I'm so curious what your scaffolding sounds like during these types of exercises.

[mathmarm]

23 minutes ago, square_25 said:

I'm not sure why there was a "confused" reaction on my post? I'm merely explaining where I'm coming from, which sounds like it's from a slightly different place than you are. 

Because I was confused from reading it. It's not a sign of disapproval. I simply had trouble following that post the first few times that I read it.  (I always read each post in its entirety if I'm going to respond to it.)

Initially I didn't see the parallel between 3(4*5) and (xy)^3, but in re-reading it, I realized that you might have used it because (xy)^3 yields 3 basic factors.
But where (xy)^3 I immediately see the 3 identical factors the numerical example that you used had 3 distinct factors and I didn't immediately see the connection.

Also you said that when she got (xyy)(xxy)(xy) "she should've realized that there was no way that that could work" but I perceived a path that would lead to that but make perfect sense, so again I was confused about why you'd say that there was no way that her result could work. It didn't seem to come from nowhere in my mind. If she'd followed through from

(xyy)(xxy)(xy) she would've eventually gotten x^4y^4, which would at least provide a clue as to where she went wrong and she might've been able to trouble-shoot her own process and find her mistake. I don't know.

There isn't wider-context to her solution. It could've been the result of nonsensical symbol-shuffling, but it could've been the result of a reasoned approach to the problem.

Of course, (xyy)(xxy)(xy) is completely wrong, and shouldn't even appear in the process of working out (xy)^3, but (depending on the context) it's not an utterly baseless mistake to make.
It doesn't strike me as a random, out-of-nowhere mistake. Which is why I was curious as to what lead to that line, what followed it, etc.

Especially for a small child, I would look at that think that their hand and mind had fallen out of sync during that problem.

I have seen many a highly competent student think faster than their hand, or have their hand move faster than their thinking. It happens to average and below average students as well. That they will think (but not write) a variable or operation or step.
Many negatives vanish for no reason, but when you trace back through, many times you can tell if the kid simply didn't write it/it got erased and wasn't replaced or if the kid dropped it because they're clueless.

I imagine that your daughters arrival to (xyy)(xxy)(xy)  wasn't utterly baseless. To me, it looks like she simply wrote too many x's and y's in the midst of her manipulations (which might've been very tedious or might not have been, IDK).
 

Anyway, I found that particular post very difficult to parse out. It's not that I disapprove of your approach, that post was just not very clear to me. But I acknowledge that there is a lot of context missing from your daughters approach.

But I think I get it now (probably).

 

[mathmarm]

Exponentiation isn't commutative. 🙂

[Cake and Pi]

1 hour ago, square_25 said:

 

Well, you can visualize it, but you still tend to visualize it with "sample numbers," right? You can't actually visualize an x or a y. I know sometimes you visualize sort of... a fuzzy version of a number? But still, there has to be SOMETHING to visualize, even if in some sense you're visualizing something general. 

My kiddo doesn't like manipulatives and is mixed on visuals. She definitely thinks of SOME things visually -- if you get her to explain why ab = ba, she does it visually. But she didn't want to use visuals for fractions at all. I don't know why. She's strong with fractions, though: it took her a bit of time, but she figured out formulas for

a/b + c/d, a/b - c/d, a/b*c/d, a/b/(c/d)

from first principles. And she can do most fraction calculations very quickly. 

We've done a bunch of mental math, which may be why she does some things verbally: we started fractions verbally, and it may be that it lingered. And we're overall a very verbal as well as a very mathy family. So that may be part of it. 

When I visualize it, it looks a great deal like the Algebra Lab Gear blocks, possibly because that's how I originally learned way back in the day. So no, no sample numbers in my head, unless you consider visualizing something like c-rods to be visualizing sample numbers. I asked DS 8 to explain his thinking on (x+y)^2 and he quickly traced out boxes in the air. He said he could "see" them in the air as a table of boxes with letters inside them. I asked him if he imagined the letters as numbers and he said they weren't any particular number but letters that acted like numbers and were sort of like all numbers at once.

He did a lot of self-discovery of properties, too, but he did it mostly with manipulatives and drawings. For example, he figured out the basics of exponents by playing with 1" plastic tiles and wood cubes. It didn't even occur to me that I should provide vocabulary like distributive property or associative property back then. He got all of the terminology through AoPS. (More proof that I'd suck at teaching without curricula to follow!)

I love how you and mathmarm focus so much on naming the properties and proving work with appropriate vocabulary. I feel like it must add an extra layer of understanding for kids with that balanced ability profile. My DS 8 is exceptionally lopsided... I guess "specialized" would be the more positive way to spin it, lol.

Anyway, I find it super interesting to see the different ways these mathematically precious kiddos unfold. I should share some of DS 8's messy, all-over-the-place, step-skipping work from when he was 6-7. It makes the handwritten stuff both of you guys shared look like works of art!

[mathmarm]

3 hours ago, Cake and Pi said:

See, and I don't think my DS 8 uses the pattern at all for things that can be visualized. The way he talks when he explains his work, it sounds like commentary on visuals, and he uses his hands to shape ideas in the air.

Jr does too! It's so neat to watch him. We could never tell if it's because he's fluent in ASL, math manipulatives or both.  Nice to have that additional data point!

34 minutes ago, Cake and Pi said:

He did a lot of self-discovery of properties, too, but he did it mostly with manipulatives and drawings. For example, he figured out the basics of exponents by playing with 1" plastic tiles and wood cubes. It didn't even occur to me that I should provide vocabulary like distributive property or associative property back then. He got all of the terminology through AoPS. (More proof that I'd suck at teaching without curricula to follow!)

I love how you and mathmarm focus so much on naming the properties and proving work with appropriate vocabulary. I feel like it must add an extra layer of understanding for kids with that balanced ability profile. My DS 8 is exceptionally lopsided... I guess "specialized" would be the more positive way to spin it, lol.

Personally I sprinkled in terminology in amongst the loads and loads of manipulative-based work that we did. We've been through arithmetic a few times now, and with each cycle, I added a slightly stronger emphasis on getting him to notice and talk about concepts and then layered in the terminology for the concepts that he was seeing. One of the reasons that we're able to now give attention and focus to the terminology, and organization of written work is because everything else is in place. Largely due to the manipulative work we did.

We did so.much with manipulatives, for so long, before we stretched to include anything else.

 

Quote

 I should share some of DS 8's messy, all-over-the-place, step-skipping work from when he was 6-7. It makes the handwritten stuff both of you guys shared look like works of art!

If you're comfortable, please do! I think it's utterly precious to see kids stuff.