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What is the best way to teach 8+5 ?


blessedmom3
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For my son, he just "sees" the Right Start abacus. So for that one, he would see eight and two "filling up" the ten, and then three sticking out leftover. You can see it because each five are a different color.

 

He never did memorize his facts. He just does stuff like that really fast.

 

Julie

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Actually I do it both ways. We do a fact sheet or flashcards. At first we are just learning and I don't relly time her or drill for speed. (but now that she is 9 I do).

 

However when I see she has a problem remembering a fact I will say that "8 is a hungry bug and wants to be 10"

 

So if he wants to just memorize it, let him.

 

Linda

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1. Do you teach it "8 wants to be a 10 so you borrow 2 from 5 and 5 becomes 3 so 10+3 =13" ? I've tried to do it this way and my child said "Mom , let me just memorize it , why complicate things ?" (he is only 6 )

 

2. Do you just make your child memorize the fact ?

3 Another way ?

 

I have one like that too! I would tell him that he's right, it would be easier just to memorize it, but that sometimes little tricks are what help facts like that stick in your brain. In this case, the trick is knowing that some numbers can borrow from each other to make the math fact easier to understand.

 

Then I'd teach it both ways.

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1. Do you teach it "8 wants to be a 10 so you borrow 2 from 5 and 5 becomes 3 so 10+3 =13" ? I've tried to do it this way and my child said "Mom , let me just memorize it , why complicate things ?" (he is only 6 )

 

2. Do you just make your child memorize the fact ?

3 Another way ?

 

I do teach "re-grouping" so 8 takes 2 from 5 (leaving 3) and one ten plus three units equals 13.

 

A "memorized" math fact that can't be explained does not count. Mean Dad.

 

And the term "borrowing" is banished from our math lessons in favor of re-grouping.

 

Bill (son aged 5)

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I think the optimal way is to let your child work it out in his own way.

 

Different people work out arithmetic in different ways, and your own way is always going to be heaps easier than somebody else's. Eg 38+24. Some people will say 30+20 is 50, 8+4 is 12, so the 50 plus the 12 is 62. If that's your method, it will look like the only logical way to do it. However, another person might say, well 38 is nearly 40. 40+24=64, take away the 2 to get the 40 back to 38, leaves 62.

 

I looked at your way and had to read over it 3 times before I got it, because it seemed so unnecessarily complicated!

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I think the optimal way is to let your child work it out in his own way.

 

Different people work out arithmetic in different ways, and your own way is always going to be heaps easier than somebody else's. Eg 38+24. Some people will say 30+20 is 50, 8+4 is 12, so the 50 plus the 12 is 62. If that's your method, it will look like the only logical way to do it. However, another person might say, well 38 is nearly 40. 40+24=64, take away the 2 to get the 40 back to 38, leaves 62.

 

I looked at your way and had to read over it 3 times before I got it, because it seemed so unnecessarily complicated!

 

What I love about Singapore Maths! They teach both (and more I think) and the student uses the one that makes most sense (and sometimes it varies).

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while I appreciate the memorization, understanding the 10 really gives a true understanding of math conceptually and place value. In my experience, if you allow for the memorization, you'll "pay for it" later when you see they really don't have a concept of place value. Finding ways to make 10's is really important for later.

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1. Do you teach it "8 wants to be a 10 so you borrow 2 from 5 and 5 becomes 3 so 10+3 =13" ?

 

My 9 yo dd does it basically this way. I do it the 5 + (5+3) and up until I started teaching math I actually counted on my fingers. Believe it or not I was quite good in math and went thru college calculus counting on my fingers.

 

My advice is to explain it different ways and see what he likes. As long as he understands the concept (which I think 5+8 is pretty obvious with a few manipulatives) let him do it the way that makes sense to him.

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I think that as long as he understands the concept of 8+5=(8+2)+3, memorising is just fine. It is really important, though, that he understands the concept of "making groups of 10" as this is really foundational in maths (as a forerunner to carrying groups of ten). Let him know that memorising makes things quicker, but that he won't always be able to memorise everything.

 

When dd and I come up against this sort of thing, I often jump her ahead by guiding her through a problem that is beyond her current maths level. This makes it clear that what we are learning now is a step towards something greater. So I might show her long multiplication when we are doing simple multiplication in response to a comment like "Yes, but we can't multiply 22x34". I don't really expect her to internalise the concept of long multiplication, but I think showing her the links between aspects of maths is helpful.

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And the term "borrowing" is banished from our math lessons in favor of re-grouping.

 

I always dispised the term "borrowing" in regards to arithmetic. Really, when are you going to give it back? Isn't that kind of rude, to borrow something and not give it back?

 

(Maybe that's why my 2nd grade teacher hated me.)

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I always dispised the term "borrowing" in regards to arithmetic. Really, when are you going to give it back? Isn't that kind of rude, to borrow something and not give it back?

 

(Maybe that's why my 2nd grade teacher hated me.)

 

My kind of thinker, you are :D

 

Bill

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I'd do it two or three ways with my DD. We'd look at it on a number line, and with the cuisenaire rods, which helps with the regrouping concept since they go up to 10 units. Once sure she gets it, I'd start her in on memorizing the facts.

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I'd do it two or three ways with my DD. We'd look at it on a number line, and with the cuisenaire rods, which helps with the regrouping concept since they go up to 10 units. Once sure she gets it, I'd start her in on memorizing the facts.

Yep, that. Memorizing is great, but it's important to actually understand the concept as well, so you don't memorize 'facts' that seem as random as "apple plus car equals rabbit".

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All of the above. My personal favorite is to say "Let's *BREAK* this five into two and three and..." together with a nice smashing motion, lol, but only one of my kids seemed to find that as delightful as I do. :) I think it's fine to memorize, but understanding that 5+8 can be the same as 5+(5+3) *or* (3+2)+8, etc, is pretty vital to a good grasp of arithmetic... But at 6, I think it's okay to do a little of both. It comes more naturally to some kids than to others. It's just important to keep *playing* with numbers so that eventually that comes...

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All of the above. My personal favorite is to say "Let's *BREAK* this five into two and three and..." together with a nice smashing motion, lol, but only one of my kids seemed to find that as delightful as I do. :) I think it's fine to memorize, but understanding that 5+8 can be the same as 5+(5+3) *or* (3+2)+8, etc, is pretty vital to a good grasp of arithmetic... But at 6, I think it's okay to do a little of both. It comes more naturally to some kids than to others. It's just important to keep *playing* with numbers so that eventually that comes...

 

Similar tactic here: the 8 will take 2 from the 5 by force (probably either with a sword or a dagger) in order to be at 10. It's boy math. :D

 

I say let him just memorize it. You can keep working on number concepts while you do your instruction, though.

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Similar tactic here: the 8 will take 2 from the 5 by force (probably either with a sword or a dagger) in order to be at 10. It's boy math. :D

 

I say let him just memorize it. You can keep working on number concepts while you do your instruction, though.

 

Ohhh, I love the idea of boy math! My oldest just gets it, but my 3yo is a memorizer. The kid can easily memorize anything and I have a feeling he'll be more like the OP's ds. But...I don't think he'd be able to resist swords and daggers. I'll have to file that away for future use.

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For bigger number like that she can't seem to memorize yet, I have her put up five fingers. Look at the 8 and say it, then go to her fingers and start counting at 9,10,11,12,13. We do this with Subtraction too, except count backwards.

Always put up the smallest number on fingers, either add up or add down.

If I waited for my Dd to memorize her facts, we'd still be in 1st grade. LOL

HTH

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I show it with C rods. My ds *sees* the rods - he regroups in his head. After they get the concept though - let the boy memorize! Kids come up with all kinds of methods for getting those facts fast....I think the important thing is to make sure he understands with real life objects AND to make sure his brain does those mental gymnastics daily. When he gets bored with adding apples on worksheets, play store with real money (trading pennies for dimes is a fun way to "regroup" without feeling so much like math LOL).

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:D Well, I have to agree with your son (up to a point). That did seem complicated to me. I have never seen math taught that way. There is a school of thought that says you can learn a lot of math by memorizing or copying it. Queen homeschool sells a math copybook. I do think understanding it is important too. So, I would say a blend of both. However, maybe your son just needs a different way to learn math (including memorizing some facts.)

 

 

Woolybear

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