'Nother Singapore question (2A) - subtraction with renaming

[Guest]

I gave in and am trying to do Singapore (again) - I am going to ask too many questions, though. Sigh.

 

So, for addition with renaming, what I gathered from the text was that when they gave us vertical problems we were supposed to carry, but for the horizontal programs, I had my son write them out in expanded form to solve:

 

127 + 535 = 600 + 50 + 12 = 662; whereas the same vertical problem we would add 5+7, write the two and carry the 1 and so on and so forth.

 

We got to subtraction today, and we get the vertical (borrowing), but I wasn't sure what to do with the horizontal problems?

 

562 - 34 =

 

How am I supposed to tell him to solve this?

 

Sorry, I feel really stupid. :(

 

ETA: The vertical/horizontal problems I am talking about are in the textbook.

[Five More Minutes]

Do you have the HIG to go along with this? I've found it to be really helpful in figuring out how to present the different concepts.

 

The vertical algorithms are used as a way of keeping track of the regrouping.

 

The example you have could be done mentally in a couple of ways:

 

(1) 562 - 34 = (500 + 60 + 2) - 30 - 4 = 500 + 30 + 2 - 4 = 500 + 28 = 528 (I'd never ask my student to write all of that; I'm just trying to map out the thinking. Basically you take the tens away first, and then use your typical regrouping to subtract the ones.)

 

(2) The "bump" as we like to call it: 562 - 34 = 560 - 32 = 530 - 2 = 528 (You bump both the subtrahend and minuend up or down the same amount to make the numbers easier to work with.)

 

Those are the two that come to mind right now; I'm sure there are others!

[boscopup]

Horizontal problems are done using mental math techniques. I haven't taught this level yet, but I just pulled out 2A HIG to see what they want you to do... I'm guessing that you'd asy:

 

562 - 34

../\

550 + 12

 

550 -30 = 520

12 - 4 = 8

So the answer is 528.

 

OR in the upper levels, I think they'd teach to do something like:

 

562-34 = 568-40 = 528

 

That's easier than the first way I did it. Just add 6 to both numbers and the difference is still the same. I don't think that's been taught at this level though?

 

Now I'm not sure how exactly they want you to write that out in the problem. It's mental math, so the kid can do it any way they want. I wouldn't make them write out all the steps if they don't need to.

 

No need to feel stupid! I think the ONE page in the HIG explaining this type of mental math is a bit slim. They usually have better explanation than that. :tongue_smilie: According to the chapter intro, this will be expanded on in 2B and 3A.

[Guest]

Oh yuck! Okay, well I don't feel as stupid now. I don't have a HIG for this level, as HOD had said I shouldn't need it. ;) Hm. I will see how the rest of this book progresses and consider getting it. Thanks for sharing the mental process, both of you. Makes more sense to me now.

[Susie in MS]

Thank you! You just helped me to get rid of any tiny lingering desire to try SM again. I know that was not the intention of this thread, but it was of great help to me.

[Guest]

Thank you! You just helped me to get rid of any tiny lingering desire to try SM again. I know that was not the intention of this thread, but it was of great help to me.

 

Ha! It's making me rethink all of the SM books I just got in the mail yesterday!!! :/

[Guest]

Boscopup & Lynnita -

 

So how much emphasis should I be putting on mental math? The text didn't tell me that, so now I'm wondering if we have been totally missing an element of the program.

[Five More Minutes]

Mental math is a pretty big part of the program, the idea being that the student first solves problems mentally (using manipulatives as needed to start) before moving to the algorithm. If I remember correctly, we spent several days doing those types of subtraction problems: first entirely with manipulatives and a place value chart; then just with the numbers in the place value charts, and then just thinking it through. Then we introduced the algorithm, and we often solved problems both ways: first mentally, then using the algorithm, and talking about which way was better for different situations.

 

I think that you'll spend a good chunk of time at the beginning of 2B practicing mental math, so this will all come up again. It was since hitting 2B that I've started using the Mental Math sections at the back of the (HIG) books much more regularly, as they give an ongoing reinforcement of the types of problems that students should be able to think through mentally.

 

Some of the mental math activities at Education Unboxed will give you a close approximation to the methods introduced in the HIGs. I've used a lot of these in 2A/2B.

[Five More Minutes]

Okay, well I don't feel as stupid now. I don't have a HIG for this level, as HOD had said I shouldn't need it. ;)

 

 

That sort of recommendation frustrates me. I'm comfortable with math, but I wouldn't want to be doing this with only the textbook to guide me. The HIG is an important component of the program. It's one thing to have another homeschooling parent say that they didn't use it for reason x, y, or z, but it's another thing to have a company giving the impression that parents *should* be able to do this without the HIG. :blink:

 

Singpaore Math is learned differently from the way I learned math, and the HIG helps me figure out how to teach it. And 2A/2B are foundational years for some of the mental math coming up, so I think it's important to nail those concepts in these years.

 

Okay. Rant over. All I really wanted to say was that you shouldn't feel stupid. :blush:

[Chelli]

I use MIF and the way they would show to do that problem is to subtract the higher ten then add back what isn't needed.

 

562-34=

 

562-40=522

 

522+6=528

 

I use and love HOD, but I believe that Carrie's recommendation to not use the HIG to teach Singapore math is very, very faulty. Most parents in this country were not taught how to do Asian math. We usually need the hand holding that an HIG or a really detailed student textbook (like MIF) provides.

[Guest]

That sort of recommendation frustrates me. I'm comfortable with math, but I wouldn't want to be doing this with only the textbook to guide me. The HIG is an important component of the program. It's one thing to have another homeschooling parent say that they didn't use it for reason x, y, or z, but it's another thing to have a company giving the impression that parents *should* be able to do this without the HIG. :blink:

 

Singpaore Math is learned differently from the way I learned math, and the HIG helps me figure out how to teach it. And 2A/2B are foundational years for some of the mental math coming up, so I think it's important to nail those concepts in these years.

 

Okay. Rant over. All I really wanted to say was that you shouldn't feel stupid. :blush:

 

 

I'm frustrated, too. Reading your answers here, I'm seriously re-thinking if Singapore is the route we want to go with. I mean, I feel that I need to do a program and do it completely. If another program works for us that is completely different than Singapore (but I am doing it completely), than I feel that would be a better choice than doing Singapore halfway.

 

Oh, and thank you for all the info. above, as well, in regards to the mental math.

[alisoncooks]

Thank you! You just helped me to get rid of any tiny lingering desire to try SM again. I know that was not the intention of this thread, but it was of great help to me.

LOL, I was somewhat thinking the same thing! :D :D

[Five More Minutes]

Reading your answers here, I'm seriously re-thinking if Singapore is the route we want to go with. I mean, I feel that I need to do a program and do it completely. If another program works for us that is completely different than Singapore (but I am doing it completely), than I feel that would be a better choice than doing Singapore halfway.

 

 

Oh, dear. I'd hate to think I'm discouraging you from using Singapore by what I've said, either in explaining that problem with ridiculously long equations in an attempt to show my thinking, or by talking about the importance of mental math. I'm sure that's not the case, but I'm going to try to expand a bit ...

 

It's not a giant leap for you to move from relying on the text only to using the full Singapore program. The mental math is a significant component of the program, simply because it is so closely linked to the conceptual understanding of numbers underlying the program. However, it doesn't necessarily take a lot more time than what you're already doing. It's integrated into the whole approach and then a couple of sections spend extra time on special mental math strategies.

 

I find things work best (and I believe that this is in line with the "Singapore way") if I start with manipulatives and let my student use those as long as they are helpful. So it's really okay if we get to the end of the subtraction chapter and my student is still grabbing the c-rods and flats to figure out 562-34 mentally. It's important that she is comfortable with seeing the numbers grouped and re-grouped, and manipulatives help. She eventually gets to the point where it's faster for her to regroup the numbers in her head than to manipulate the rods.

 

And fwiw, you got me thinking, and I actually dug out my 2A HIG and looked back at the topic where I *think* you are. (Unit 2, Ch. 5 is where I looked.) According to the HIG, one of the points of the horizontally-written problems in the text is to have the student first work it out with manipulatives (they suggest discs; I used c-rods), and then write the problem vertically and figure it out that way to compare. The mental math "tricks" emerge through using the manipulatives and then later on through more explicit teaching in 2B.

[Guest]

Lynnita -

 

No, it wasn't you that discouraged me. (Or anyone in particular who posted here.) It was just kind of a "this 10 minute math seems too good to be true...oh, wait, what in the world are they asking for now? Oh, wait, I need to order word problem books now? Oh, wait, now I need the HIG?"...kind of thinking that just got me down this morning. There's nothing worse than my son asking why a curriculum is doing something and I am clueless. I am determined to give Singapore one last valiant effort, in hopes that it will stick, remembering that just because we use Singapore doesn't mean that my kids are math geniuses. It can work for normal people, too. (Right? Right? lol )

 

I did order the Process Skills books and got those yesterday. I ordered the 2A HIG after our discussion and it should be here tomorrow or Thursday. Since I got those FAN books, I don't need the CWP, and I don't think we need the IP books, either. So, that should be a good, solid math for us. Math has been discouraging for us this year. We started in one math that was way too easy, skipped an entire year and then finished that. Then, I didn't want to move forward, but sideways and found that we were actually behind in many different math curricula than where we had been in our original one. Basically, I thought we were so far ahead, and now I am realizing we are not. And we can't solve word problems. And we can't do mental subtraction. :)

 

Just had to get that out. I am looking forward to getting my HIG in the mail and moving forward. :)

[poiema]

I did order the Process Skills books and got those yesterday. I ordered the 2A HIG after our discussion and it should be here tomorrow or Thursday. Since I got those FAN books, I don't need the CWP, and I don't think we need the IP books, either.

Will you please tell me what the Process Skills books and FAN books are? So that I can have even more books to consider. :willy_nilly:

[Guest]

Will you please tell me what the Process Skills books and FAN books are? So that I can have even more books to consider. :willy_nilly:

 

I had them recommended to me here and then searched and found a few threads about them. Here is one of the ones I ordered from CBD, although I believe you can buy them elsewhere, including the Singapore website. I ended up going with these over the Challenging Word Problems, because it sounded like they had a little better explanation and were a bit more thorough, for those of us who are a bit slower. ;)

[Spy Car]

 

 

I'm frustrated, too. Reading your answers here, I'm seriously re-thinking if Singapore is the route we want to go with. I mean, I feel that I need to do a program and do it completely. If another program works for us that is completely different than Singapore (but I am doing it completely), than I feel that would be a better choice than doing Singapore halfway.

 

Oh, and thank you for all the info. above, as well, in regards to the mental math.

 

Or do Singapore the whole way, as it is really awesome!

 

Bill

[Dana]

 

I had them recommended to me here and then searched and found a few threads about them. Here is one of the ones I ordered from CBD, although I believe you can buy them elsewhere, including the Singapore website. I ended up going with these over the Challenging Word Problems, because it sounded like they had a little better explanation and were a bit more thorough, for those of us who are a bit slower. ;)

 

 

They do have a better explanation...but they don't have what I'd consider "enough" practice with word problems.

CWP has about 20 problems (typically) for a topic. iExcel has 4 or 5 per section. They will have multiple sections for a topic, but they'll entirely skip other topics. For instance, 5 doesn't have any geometry. It only has whole numbers, fractions, decimals, and percents. So I'd still suggest using IP or CWP in addition.

[lluv]

Thanks so much for posting this, the comments are helpful. We are doing the same section and it's been difficult for my 7 year old, so we've been spending extra time on it. He can do it reasonable well with the c-rods and flats, but still needs help with the mental math portion. I have Math Mammoth as well, so I've been pulling out the corresponding worksheets and having him work through those.

 

Should we simmer in this section for a while or just move on...any suggestions?

[Five More Minutes]

Thanks so much for posting this, the comments are helpful. We are doing the same section and it's been difficult for my 7 year old, so we've been spending extra time on it. He can do it reasonable well with the c-rods and flats, but still needs help with the mental math portion. I have Math Mammoth as well, so I've been pulling out the corresponding worksheets and having him work through those.

 

Should we simmer in this section for a while or just move on...any suggestions?

 

The first section of 2B is devoted to addition and subtraction, so it will come up again very soon. You know your student best ... if he gets the concepts but just needs to take time working things out with the c-rods & flats, then you could start to move on. I think it would be valuable to review addition / subtraction with renaming several times a week (or daily) for 5-10 minutes a day, either using the Mental Math in the HIG, Intensive Practice, CWP, Math Mammoth, or questions you make up (and do on the whiteboard?).

 

If he's not super-confident doing these problems with the c-rods yet, then it might be wise to let it simmer a bit longer before moving on. And I'd still reinforce regularly once you move on, as it seems you're doing.