Singapore Dimensions 4A Mental Math

[Ting Tang]

My son (I suspect he is ASD, year long wait for eval) is on the 2nd chapter of Dimensions 4A.  He seems to be on the right track doing mental math, but he got so many problems wrong on his workbook exercises today.  I am perhaps not the best to teach this in a clear, concise manner, either.  I love algorithms.  He can certainly use a standard algorithm to subtract from 10,000....but regrouping and doing it in his head is challenging.  I am considering using teaching videos.  But for those who've gone through Singapore math of any sort, how essential is using the mental math strategies for subtraction?  It does teach the traditional methods, too, but the point of this exercise was mental math.  If he would have done it all the traditional way, few would have been incorrect.  

Edited September 15, 2022 by Ting Tang

[Malam]

https://www.rainbowresource.com/product/049616/Singapore-Math-Mental-Math-Grade-4.html

https://singaporemathsource.com/mathexpress-speed-maths-strategies/

https://www.amazon.com/MathExpress-Speed-Maths-Strategies-Fan-Math/dp/9810582595 (3 and 4 don't have as much subtraction practice)

Can he rapidly subtract from 100?

Can he solve 58 + 37 by either moving 3 from 58 to 37 or moving 2 from 37 to 52?

Edited September 15, 2022 by Malam

[Ausmumof3]

I think it depends a lot on the kid. My kids do stuff on their heads they wouldn’t attempt thanks to Singapore. Unfortunately sometimes this results in cognitive overload and they’d be better writing more down. In higher math, I’ve really had to work to get them to write down working because they like to do everything mentally.

However, with real life being able to do quick mental calculations is super handy when shopping, doing price comparisons, measuring up a room etc so I think it’s worth it if it’s doable. But for some of my tutor kids mental math is a bad idea - they have slow processing speed or poor working memory and writing things down enables them to actually manage the problems without errors, like taking tens from ones or not regrouping correctly. But I only have a few minutes a week with them - not enough to really teach the strategies well. So if there are any kind of challenges with working memory etc, I think having really solid grasp of the algorithms is much more important.

The one skill that I do think is pretty important is being able to bridge through ten pretty rapidly, and use the commutative property as I have kids come in Y6/7 and they still count on fingers for numbers like eight or nine (for example they will do 3+8 by counting up 8 on their fingers - even if they can’t retain facts it would be so much easier if they just did 8 and counted on 3).

[Lucy the Valiant]

What we did with our kids in SM: We taught them SM's mental math, and practiced it until they were fast & comfortable. We *then introduced the standard algorithm's so they would know what other people were talking about if it came up. And then they had multiple tools and could choose which tool suited each problem best. 

We use SM up through 6B and then switch to Houghton / Dolciani at pre-algebra. This has worked well for multiple kids here, though (*wink) I'm sure there are many valid pathways. (I am not "mathy" but needed to teach math up through Alg 2 / Trig; kids got a tutor at pre-calc / calc.)

[Ting Tang]

23 hours ago, Malam said:

https://www.rainbowresource.com/product/049616/Singapore-Math-Mental-Math-Grade-4.html

https://singaporemathsource.com/mathexpress-speed-maths-strategies/

https://www.amazon.com/MathExpress-Speed-Maths-Strategies-Fan-Math/dp/9810582595 (3 and 4 don't have as much subtraction practice)

Can he rapidly subtract from 100?

Can he solve 58 + 37 by either moving 3 from 58 to 37 or moving 2 from 37 to 52?

Thank you! I am going to check these out.  We went over the ones he missed today, and he was doing so much better.  But maybe we could benefit from some help.

 

[Ting Tang]

20 hours ago, Ausmumof3 said:

I think it depends a lot on the kid. My kids do stuff on their heads they wouldn’t attempt thanks to Singapore. Unfortunately sometimes this results in cognitive overload and they’d be better writing more down. In higher math, I’ve really had to work to get them to write down working because they like to do everything mentally.

However, with real life being able to do quick mental calculations is super handy when shopping, doing price comparisons, measuring up a room etc so I think it’s worth it if it’s doable. But for some of my tutor kids mental math is a bad idea - they have slow processing speed or poor working memory and writing things down enables them to actually manage the problems without errors, like taking tens from ones or not regrouping correctly. But I only have a few minutes a week with them - not enough to really teach the strategies well. So if there are any kind of challenges with working memory etc, I think having really solid grasp of the algorithms is much more important.

The one skill that I do think is pretty important is being able to bridge through ten pretty rapidly, and use the commutative property as I have kids come in Y6/7 and they still count on fingers for numbers like eight or nine (for example they will do 3+8 by counting up 8 on their fingers - even if they can’t retain facts it would be so much easier if they just did 8 and counted on 3).

Thank you! This is exactly what I told him today, that this skill would be useful.  He did much better today with it.  Still, I hope that it is perfectly okay to also use standard algorithms.  I was really hoping that Singapore would just give him a conceptual understanding, without confusing him too much!  He's pretty good with addition and subtraction, but I know his weaker area will be division--and that i where I am hoping Singapore will help, once we get back to that.

[Ting Tang]

18 hours ago, Lucy the Valiant said:

What we did with our kids in SM: We taught them SM's mental math, and practiced it until they were fast & comfortable. We *then introduced the standard algorithm's so they would know what other people were talking about if it came up. And then they had multiple tools and could choose which tool suited each problem best. 

We use SM up through 6B and then switch to Houghton / Dolciani at pre-algebra. This has worked well for multiple kids here, though (*wink) I'm sure there are many valid pathways. (I am not "mathy" but needed to teach math up through Alg 2 / Trig; kids got a tutor at pre-calc / calc.)

Thanks! The Dimensions shows both, which I really like, but I did just wonder if it was super important for the future.  I can see how this would be practical, but I also don't want to overcomplicate things he knows how to do already.  🙂  Fortunately, today went better, reviewing the ones he missed.