Cardinal Math

Addition with regrouping · sheet 24 of 30

Answer key

The answer, and what a wrong answer means.

The sheet
#ProblemAnswerIf they wrote…
1 12 + 38 50 40 forgets the ten410 writes the whole column sum
2 53 + 48 101 91 forgets the ten911 writes the whole column sum
3 209 + 467 676 6616 writes the whole column sum666 forgets the ten766 carries two columns over
4 198 + 277 475 1465 carries two columns over31615 writes the whole column sum365 forgets the ten
5 443 + 196 639 1539 carries two columns over5139 writes the whole column sum539 forgets the ten
6 23 + 38 61 51 forgets the ten511 writes the whole column sum
7 188 + 117 305 2915 writes the whole column sum295 forgets the ten395 carries two columns over
8 139 + 469 608 5918 writes the whole column sum598 forgets the ten698 carries two columns over
9 296 + 110 406 1306 carries two columns over306 forgets the ten3106 writes the whole column sum
10 159 + 535 694 6814 writes the whole column sum684 forgets the ten784 carries two columns over
11 598 + 267 865 1855 carries two columns over71515 writes the whole column sum755 forgets the ten
12 494 + 328 822 1812 carries two columns over71112 writes the whole column sum712 forgets the ten
13 81 + 19 100 90 forgets the ten910 writes the whole column sum
14 14 + 78 92 812 writes the whole column sum82 forgets the ten
15 109 + 298 407 3917 writes the whole column sum397 forgets the ten497 carries two columns over
16 14 + 76 90 80 forgets the ten810 writes the whole column sum
17 280 + 395 675 1575 carries two columns over5175 writes the whole column sum575 forgets the ten
18 63 + 18 81 71 forgets the ten711 writes the whole column sum
19 22 + 58 80 70 forgets the ten710 writes the whole column sum
20 407 + 359 766 7516 writes the whole column sum756 forgets the ten856 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.