Cardinal Math

Addition with regrouping · sheet 8 of 30

Answer key

The answer, and what a wrong answer means.

The sheet
#ProblemAnswerIf they wrote…
1 39 + 43 82 712 writes the whole column sum72 forgets the ten
2 83 + 19 102 912 writes the whole column sum92 forgets the ten
3 494 + 190 684 1584 carries two columns over5184 writes the whole column sum584 forgets the ten
4 139 + 616 755 7415 writes the whole column sum745 forgets the ten845 carries two columns over
5 38 + 39 77 617 writes the whole column sum67 forgets the ten
6 46 + 18 64 514 writes the whole column sum54 forgets the ten
7 26 + 25 51 41 forgets the ten411 writes the whole column sum
8 118 + 528 646 6316 writes the whole column sum636 forgets the ten736 carries two columns over
9 646 + 278 924 1914 carries two columns over81114 writes the whole column sum814 forgets the ten
10 590 + 370 960 1860 carries two columns over8160 writes the whole column sum860 forgets the ten
11 274 + 129 403 3913 writes the whole column sum393 forgets the ten493 carries two columns over
12 596 + 108 704 6914 writes the whole column sum694 forgets the ten794 carries two columns over
13 494 + 291 785 1685 carries two columns over6185 writes the whole column sum685 forgets the ten
14 15 + 18 33 213 writes the whole column sum23 forgets the ten
15 37 + 63 100 90 forgets the ten910 writes the whole column sum
16 116 + 187 303 2913 writes the whole column sum293 forgets the ten393 carries two columns over
17 278 + 294 572 1562 carries two columns over41612 writes the whole column sum462 forgets the ten
18 186 + 759 945 1935 carries two columns over81315 writes the whole column sum835 forgets the ten
19 17 + 66 83 713 writes the whole column sum73 forgets the ten
20 108 + 148 256 2416 writes the whole column sum246 forgets the ten346 carries two columns over

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 in the guide. Problems marked "no pattern to catch" are the plain ones; a child who gets only those right is telling you something too.

Writes the whole column sum 20 of 20 problems

Writes each column's full total into the answer: 8 and 5 are 13, so 13 goes down; 3 and 4 are 7.

38 + 45 they write 713 it is 83

Forgets the ten 20 of 20 problems

Adds each column and keeps only the ones digit of the total. The ten that should move left gets dropped.

38 + 45 they write 73 it is 83

Carries two columns over 12 of 20 problems

The carried ten skips a column and lands two places left, where it's worth a hundred.

375 + 182 they write 1457 it is 557

Not sure which? The five-minute check picks the problems that tell the patterns apart and names the one it sees.