Cardinal Math

Addition with regrouping · sheet 15 of 30

Answer key

The answer, and what a wrong answer means.

The sheet
#ProblemAnswerIf they wrote…
1 161 + 319 480 470 forgets the ten4710 writes the whole column sum570 carries two columns over
2 147 + 158 305 2915 writes the whole column sum295 forgets the ten395 carries two columns over
3 21 + 19 40 30 forgets the ten310 writes the whole column sum
4 24 + 79 103 913 writes the whole column sum93 forgets the ten
5 289 + 198 487 1477 carries two columns over31717 writes the whole column sum377 forgets the ten
6 338 + 265 603 5913 writes the whole column sum593 forgets the ten693 carries two columns over
7 188 + 377 565 1555 carries two columns over41515 writes the whole column sum455 forgets the ten
8 380 + 199 579 1479 carries two columns over4179 writes the whole column sum479 forgets the ten
9 309 + 208 517 5017 writes the whole column sum507 forgets the ten607 carries two columns over
10 18 + 34 52 412 writes the whole column sum42 forgets the ten
11 15 + 27 42 312 writes the whole column sum32 forgets the ten
12 289 + 319 608 5918 writes the whole column sum598 forgets the ten698 carries two columns over
13 38 + 47 85 715 writes the whole column sum75 forgets the ten
14 12 + 88 100 90 forgets the ten910 writes the whole column sum
15 296 + 149 445 1435 carries two columns over31315 writes the whole column sum335 forgets the ten
16 625 + 108 733 7213 writes the whole column sum723 forgets the ten823 carries two columns over
17 180 + 197 377 1277 carries two columns over2177 writes the whole column sum277 forgets the ten
18 25 + 57 82 712 writes the whole column sum72 forgets the ten
19 193 + 361 554 1454 carries two columns over4154 writes the whole column sum454 forgets the ten
20 53 + 19 72 612 writes the whole column sum62 forgets the ten

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.