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"?