Answer key

The answer, and what a wrong answer means.

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

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 7 of 20 problems