Answer key

The answer, and what a wrong answer means.

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