Answer key

The answer, and what a wrong answer means.

#	Problem	Answer	If they wrote…
1	8 + 8	16	no pattern to catch here
2	6 + 1	7	no pattern to catch here
3	7 + 9	16	17 rounding to add, then forgetting to adjust
4	8 + 6	14	16 rounding to add, then forgetting to adjust
5	6 + 7	13	no pattern to catch here
6	3 + 3	6	no pattern to catch here
7	9 + 7	16	17 rounding to add, then forgetting to adjust
8	2 + 3	5	no pattern to catch here
9	2 + 1	3	no pattern to catch here
10	7 + 7	14	no pattern to catch here
11	9 + 9	18	19 rounding to add, then forgetting to adjust
12	8 + 3	11	13 rounding to add, then forgetting to adjust
13	8 + 9	17	18 rounding to add, then forgetting to adjust
14	2 + 9	11	12 rounding to add, then forgetting to adjust
15	9 + 6	15	16 rounding to add, then forgetting to adjust
16	6 + 6	12	no pattern to catch here
17	9 + 3	12	13 rounding to add, then forgetting to adjust
18	4 + 5	9	no pattern to catch here
19	4 + 3	7	no pattern to catch here
20	3 + 7	10	no pattern to catch here

Reading the wrong answers

One wrong answer is a slip. The same pattern on three or more problems is a rule your child is following, and it has a name and a fix. Problems marked "no pattern to catch" are the plain ones; a child who gets only those right is telling you something too.

Reading the wrong answers

Rounding to add, then forgetting to adjust 9 of 20 problems