**I. A 2nd grade (TERC) Investigations subtraction assignment, assigned in mid-December:**

**II. From a similar point in the 2nd grade Singapore Math curriculum (**

*Primary Mathematics 2B*, pp. 20-21):**III. Extra Credit:**

What kinds of answers can

*Investigations*parents expect from their children when they ask (as per the

**Family Connection**above) "Is it helpful to have the counting-by-5's and county-by-10's numbers shaded on the 100 chart? Why?"

Should parents worry if their child is one of those who "counts up or back by 1s" rather than "by 10's and then 5's," or "by 10's and then 1's"?

## 2 comments:

In answer to your extra credit question: Should parents worry if their child is one of those who "counts up or back by 1s" rather than "by 10's and then 5's," or "by 10's and then 1's"? My answer is: only if they do it persistently across lots of different types of problems. Grouping by 10's is actually pretty important. I wouldn't worry _too_ much in second grade if they know what they're doing when counting by 1's, but by 3rd grade if they aren't using 10's and 100's appropriately, it means that something is going wrong... possibly something with a brain chemistry aspect, and probably something that isn't going to work out all by itself.

I don't know about Singapore math, recently I have found tutorteddy math curriculum. I have bought it for my daughter; she is in 8th grade. The curriculum is extremely good, cheap and reusable.

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