Cardinal Math

Addition with regrouping · sheet 9 of 30

Answer key

The answer, and what a wrong answer means.

The sheet
#ProblemAnswerIf they wrote…
1 296 + 392 688 1588 carries two columns over5188 writes the whole column sum588 forgets the ten
2 15 + 56 71 61 forgets the ten611 writes the whole column sum
3 197 + 139 336 1326 carries two columns over21216 writes the whole column sum226 forgets the ten
4 56 + 46 102 912 writes the whole column sum92 forgets the ten
5 56 + 25 81 71 forgets the ten711 writes the whole column sum
6 289 + 113 402 3912 writes the whole column sum392 forgets the ten492 carries two columns over
7 33 + 29 62 512 writes the whole column sum52 forgets the ten
8 189 + 539 728 1718 carries two columns over61118 writes the whole column sum618 forgets the ten
9 586 + 299 885 1875 carries two columns over71715 writes the whole column sum775 forgets the ten
10 390 + 452 842 1742 carries two columns over7142 writes the whole column sum742 forgets the ten
11 109 + 199 308 2918 writes the whole column sum298 forgets the ten398 carries two columns over
12 134 + 148 282 2712 writes the whole column sum272 forgets the ten372 carries two columns over
13 448 + 170 618 1518 carries two columns over5118 writes the whole column sum518 forgets the ten
14 217 + 309 526 5116 writes the whole column sum516 forgets the ten616 carries two columns over
15 22 + 19 41 31 forgets the ten311 writes the whole column sum
16 32 + 69 101 91 forgets the ten911 writes the whole column sum
17 318 + 524 842 8312 writes the whole column sum832 forgets the ten932 carries two columns over
18 13 + 49 62 512 writes the whole column sum52 forgets the ten
19 243 + 258 501 491 forgets the ten4911 writes the whole column sum591 carries two columns over
20 33 + 18 51 41 forgets the ten411 writes the whole column sum

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.