Cardinal Math

Addition with regrouping · sheet 2 of 30

Answer key

The answer, and what a wrong answer means.

The sheet
#ProblemAnswerIf they wrote…
1 159 + 216 375 3615 writes the whole column sum365 forgets the ten465 carries two columns over
2 79 + 21 100 90 forgets the ten910 writes the whole column sum
3 76 + 16 92 812 writes the whole column sum82 forgets the ten
4 563 + 185 748 1648 carries two columns over6148 writes the whole column sum648 forgets the ten
5 149 + 359 508 4918 writes the whole column sum498 forgets the ten598 carries two columns over
6 190 + 471 661 1561 carries two columns over5161 writes the whole column sum561 forgets the ten
7 54 + 46 100 90 forgets the ten910 writes the whole column sum
8 143 + 458 601 591 forgets the ten5911 writes the whole column sum691 carries two columns over
9 648 + 138 786 7716 writes the whole column sum776 forgets the ten876 carries two columns over
10 570 + 270 840 1740 carries two columns over7140 writes the whole column sum740 forgets the ten
11 69 + 13 82 712 writes the whole column sum72 forgets the ten
12 169 + 585 754 1744 carries two columns over61414 writes the whole column sum644 forgets the ten
13 195 + 498 693 1683 carries two columns over51813 writes the whole column sum583 forgets the ten
14 14 + 19 33 213 writes the whole column sum23 forgets the ten
15 207 + 515 722 7112 writes the whole column sum712 forgets the ten812 carries two columns over
16 12 + 79 91 81 forgets the ten811 writes the whole column sum
17 14 + 57 71 61 forgets the ten611 writes the whole column sum
18 247 + 155 402 3912 writes the whole column sum392 forgets the ten492 carries two columns over
19 398 + 166 564 1554 carries two columns over41514 writes the whole column sum454 forgets the ten
20 17 + 17 34 214 writes the whole column sum24 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.