Cardinal Math

Addition with regrouping · sheet 7 of 30

Answer key

The answer, and what a wrong answer means.

The sheet
#ProblemAnswerIf they wrote…
1 399 + 298 697 1687 carries two columns over51817 writes the whole column sum587 forgets the ten
2 12 + 18 30 20 forgets the ten210 writes the whole column sum
3 688 + 219 907 8917 writes the whole column sum897 forgets the ten997 carries two columns over
4 29 + 77 106 916 writes the whole column sum96 forgets the ten
5 179 + 509 688 6718 writes the whole column sum678 forgets the ten778 carries two columns over
6 59 + 44 103 913 writes the whole column sum93 forgets the ten
7 469 + 338 807 7917 writes the whole column sum797 forgets the ten897 carries two columns over
8 209 + 209 418 4018 writes the whole column sum408 forgets the ten508 carries two columns over
9 385 + 216 601 591 forgets the ten5911 writes the whole column sum691 carries two columns over
10 62 + 28 90 80 forgets the ten810 writes the whole column sum
11 152 + 182 334 1234 carries two columns over2134 writes the whole column sum234 forgets the ten
12 23 + 18 41 31 forgets the ten311 writes the whole column sum
13 659 + 126 785 7715 writes the whole column sum775 forgets the ten875 carries two columns over
14 759 + 198 957 1947 carries two columns over81417 writes the whole column sum847 forgets the ten
15 290 + 320 610 1510 carries two columns over510 forgets the ten5110 writes the whole column sum
16 12 + 19 31 21 forgets the ten211 writes the whole column sum
17 199 + 458 657 1647 carries two columns over51417 writes the whole column sum547 forgets the ten
18 352 + 191 543 1443 carries two columns over4143 writes the whole column sum443 forgets the ten
19 37 + 34 71 61 forgets the ten611 writes the whole column sum
20 19 + 25 44 314 writes the whole column sum34 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.