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	7 + 9	16	17 rounding to add, then forgetting to adjust
3	3 + 2	5	no pattern to catch here
4	5 + 5	10	no pattern to catch here
5	5 + 4	9	no pattern to catch here
6	7 + 3	10	no pattern to catch here
7	7 + 1	8	no pattern to catch here
8	2 + 9	11	12 rounding to add, then forgetting to adjust
9	8 + 3	11	13 rounding to add, then forgetting to adjust
10	7 + 6	13	no pattern to catch here
11	8 + 8	16	18 rounding to add, then forgetting to adjust
12	7 + 6	13	no pattern to catch here
13	3 + 4	7	no pattern to catch here
14	8 + 9	17	18 rounding to add, then forgetting to adjust
15	4 + 3	7	no pattern to catch here
16	4 + 4	8	no pattern to catch here
17	5 + 8	13	15 rounding to add, then forgetting to adjust
18	8 + 4	12	14 rounding to add, then forgetting to adjust
19	9 + 9	18	no pattern to catch here
20	7 + 2	9	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 7 of 20 problems