Cardinal Math

Addition with regrouping · sheet 25 of 30

Answer key

The answer, and what a wrong answer means.

The sheet
#ProblemAnswerIf they wrote…
1 12 + 19 31 21 forgets the ten211 writes the whole column sum
2 188 + 178 366 1356 carries two columns over21516 writes the whole column sum256 forgets the ten
3 33 + 19 52 412 writes the whole column sum42 forgets the ten
4 281 + 150 431 1331 carries two columns over3131 writes the whole column sum331 forgets the ten
5 17 + 17 34 214 writes the whole column sum24 forgets the ten
6 178 + 169 347 1337 carries two columns over21317 writes the whole column sum237 forgets the ten
7 492 + 261 753 1653 carries two columns over6153 writes the whole column sum653 forgets the ten
8 167 + 339 506 4916 writes the whole column sum496 forgets the ten596 carries two columns over
9 109 + 597 706 6916 writes the whole column sum696 forgets the ten796 carries two columns over
10 103 + 269 372 3612 writes the whole column sum362 forgets the ten462 carries two columns over
11 292 + 697 989 1889 carries two columns over8189 writes the whole column sum889 forgets the ten
12 22 + 29 51 41 forgets the ten411 writes the whole column sum
13 73 + 28 101 91 forgets the ten911 writes the whole column sum
14 229 + 279 508 4918 writes the whole column sum498 forgets the ten598 carries two columns over
15 394 + 496 890 1880 carries two columns over71810 writes the whole column sum780 forgets the ten
16 359 + 127 486 4716 writes the whole column sum476 forgets the ten576 carries two columns over
17 36 + 65 101 91 forgets the ten911 writes the whole column sum
18 19 + 24 43 313 writes the whole column sum33 forgets the ten
19 24 + 18 42 312 writes the whole column sum32 forgets the ten
20 308 + 249 557 5417 writes the whole column sum547 forgets the ten647 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.