Answer key

The answer, and what a wrong answer means.

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