Q's about SM 1B

[SS in MD]

I am curious what others do -

SM 1B and on has a LOT of horizontal addition and subtraction. Is dd suppose to be able to do that in her head? Or do you all change the problem to be vertical? This had been a stumbling block for dd, and I've taught her how to (horitonally add/sub ones place then carry/borrow then add/sub tens place etc), but she still gets confused. How do you have your dc it?

Thanks so much! :)

[lotsofpumpkins]

When we get to that I'm going to let them write it vertically if they need to. I think I read somewhere that SM will present different ways to solve a problem, and the student can use the method they prefer. We just started 1A today so I haven't gotten to that yet! My oldest places into 1B but I'm letting her watch her brother do 1A first so that she sees the SM style.

[jcooperetc]

I think it is so they can manage it in their head. Singapore teaches a lot of methods to make mental arithmetic easier and it focuses on place value and thinking of numbers for what they represent instead of focusing on the algorithm. Tedious as it is at first, it does help in later levels to be able to do it in your head and to think of numbers as parts and wholes - 35 + 3 is really 30 + (5+3). At this stage it really doesn't seem much quicker to do it that way instead of counting up 35, 36, 37, 38 etc. but later on when the problems are more complicated it is much faster to do it mentally. Unless there is a lot of regrouping going on it really doesn't change anything to make it vertical anyway - it just somehow looks easier to figure out I think.

Anyway, just my opinion, for what it is worth (2 cents?) ;)

[servin]

I believe they are supposed to do it mentally with the "tricks" taught in Singapore. IT's really not tricks so much as understanding proper place nvalue and numerical value of the numbers involved. Overall, if they learn this now, they will have a far better understanding of math and be able to slip between numbers and conversions far easier than just learning to subtract or add.

Knowing that 35-3 is the same as 30 + (5-3) is a concept that actually makes understanding higher levels of math easier. To me the added benefit was they learned to add and subtract impressive numbers in their head :001_smile: I wouldn't worry about them getting the right answer(they should get the right answer) but that they really understand how to rearrange the numbers to arrive at the right answer.

I spent a lot of time in 1a and 1 b learning those methods myself and making sure the kiddos did them the way Singapore showed them because the concept was more important in my eyes than that they could do the work. And with one in Algebra, I now see how that concept has come into play more than once.

You will also run into this in multiplication. Knowing that 25*5 is actually
(20*5) + (5*5) is more important than the traditional way I was taught math. It shows the student understands place value and how to properly shift between them.

Just my 2 cents!

[matroyshka]

Yep, I made 'em do it in their heads. I don't think column addition is even taught in Singapore till 2A? I think it was well, well worth the extra time spent teaching them to regroup in their heads the Singapore way. If we had skipped that, it would have been much harder to teach later on (I'm pretty darn sure that once they learned the intially easier method that didn't require all that mental regrouping, they wouldn't have wanted to be bothered learning it the other way). I've found that Singapore really has reasons for introducing things in the order that they do - I'll wonder, "why this, now?", then another bit on, I'll see how it all builds on itself and the previous skill is foundational to something coming along soon.

[lotsofpumpkins]

I stand corrected, I guess! :)

What you all are saying makes total sense though.

[Hillary in KS]

I've taken 3 kids through SM 1 so far. Don' t skimp on the mental math problems. It pays off later!

I wouldn't recommend having her do the traditional addition algorithm in her head. It's too tedious. (Add the ones, regroup, etc.) With ds #2, he's learning addition and subtraction with money. He subtracts the dollars first, then the change.

$4.65- $3.20=
1. $4.65-$3 = $1.65
2. $1.65- $0.20= $1.45
So $4.65- $3.20= $1.45


SM is very methodical. When they introduce a new concept, the little people heads on the pages tell your child how to think of it, or gives them a hint. (Hint: Add the 100's first.)

You may want to take a few days, and go back to where those horizontal problems begin appearing and review them. Get her comfortable with the easier problems and work your way back to the lesson she's on.

[servin]

:iagree:


This is why I recommend to those who are moving into Singapore that it really is necessary to go through all the books even if they have well mastered the subject. Just to master their way of thinking. Learn it Singapore's way and you will have students who are not rattled by problems that they have never seen before and who have a better mathematical understanding than other students. They just really know math.

[Penelope]

The home instructor's guide does suggest that you show them how later it will be written vertically, and briefly demonstrating the algorithm.

But yes, I have him do all the problems horizontally. The HIG has many pages more, for reinforcement (with no pictures like the WB often has).

[siloam]

We do it mentally. For example with 53+22=? I would add the 10's place (73) then add the one's (75). For a problem with borrowing 53+58 I again start with the 10's (103) then do the one's (106), or 53+58= I would think tens (103), then do the one's with carrying (111).

Heather