Grade 2 (review in grade 3) · 2.NBT.7 · sheet 28 of 30
Three-digit subtraction with regrouping
A printable worksheet, new every day, with a key that names the mistake.
- Twenty problems across every borrow shape: none, ones only, tens only, both, and the across-zero ones like 302 − 167.
- Zeros are where subtraction goes wrong in five different ways. The key names each one from the answer your child wrote.
Three-digit subtraction with regrouping
Show your work. A zero has nothing to lend: go one more column left.
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1
424 −192
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2
603 −364
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3
678 −577
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4
760 −389
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5
341 −315
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6
436 −318
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7
606 −425
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8
405 −107
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9
369 −181
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10
245 −178
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11
978 −815
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12
683 −394
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13
605 −434
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14
408 −349
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15
774 −579
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16
507 −391
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17
164 −137
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18
570 −381
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19
706 −489
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20
421 −191
The app does this live.
It picks the next problem from the last answer, skips ahead or doubles back, and animates a hundred bursting into tens and a ten into ones instead of telling your child to cross something out. The five-minute check on the guide is the same engine in your browser, and the guide explains each of the patterns the key names.
How to use the key
Mark the sheet against the key. Beside each answer it lists what the known mistakes would have written. One wrong answer is a slip. The same pattern three times is a rule your child is following, and the guide says what to do about it tonight.
On this sheet the key can tell apart: borrows, but never pays (18 problems), smaller from larger (18 problems), zero minus a number is the number (5 problems), zero minus a number is zero (5 problems), borrowing through a zero (4 problems).
Cardinal Math watches for all of these, every day.
Inside the app the same patterns are caught as your child plays, across the whole of K to grade 5, and explained to you in plain words. One price, no ads, no streaks. Coming to iPhone and iPad.
Tell me when it's out