Cardinal Math

Addition with regrouping · sheet 30 of 30

Answer key

The answer, and what a wrong answer means.

The sheet
#ProblemAnswerIf they wrote…
1 306 + 104 410 400 forgets the ten4010 writes the whole column sum500 carries two columns over
2 190 + 180 370 1270 carries two columns over2170 writes the whole column sum270 forgets the ten
3 228 + 176 404 3914 writes the whole column sum394 forgets the ten494 carries two columns over
4 393 + 292 685 1585 carries two columns over5185 writes the whole column sum585 forgets the ten
5 173 + 395 568 1468 carries two columns over4168 writes the whole column sum468 forgets the ten
6 69 + 37 106 916 writes the whole column sum96 forgets the ten
7 278 + 169 447 1437 carries two columns over31317 writes the whole column sum337 forgets the ten
8 567 + 195 762 1752 carries two columns over61512 writes the whole column sum652 forgets the ten
9 16 + 27 43 313 writes the whole column sum33 forgets the ten
10 89 + 19 108 918 writes the whole column sum98 forgets the ten
11 115 + 687 802 7912 writes the whole column sum792 forgets the ten892 carries two columns over
12 197 + 488 685 1675 carries two columns over51715 writes the whole column sum575 forgets the ten
13 105 + 295 400 390 forgets the ten3910 writes the whole column sum490 carries two columns over
14 28 + 58 86 716 writes the whole column sum76 forgets the ten
15 56 + 14 70 60 forgets the ten610 writes the whole column sum
16 159 + 407 566 5516 writes the whole column sum556 forgets the ten656 carries two columns over
17 28 + 14 42 312 writes the whole column sum32 forgets the ten
18 17 + 13 30 20 forgets the ten210 writes the whole column sum
19 17 + 44 61 51 forgets the ten511 writes the whole column sum
20 127 + 237 364 3514 writes the whole column sum354 forgets the ten454 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.