Subtraction with Regrouping Calculator

Subtraction with Regrouping: How It Works

How it works: 604 − 256 in a column

604 − 256 in a column. Above the columns: the values after borrowing — a crossed-out digit is replaced by the number above it; +10 marks a column that received a borrowed ten.
	5	9	+10
	6(was 6, now 5)	0(was 0, now 9)	4 (was 4, now 14)
−	2	5	6
	3	4	8

With regrouping across a zero: 2 borrows — there are no tens to borrow from, so 1 hundred becomes 10 tens, and 1 ten goes to the ones

Write the larger number on top, ones under ones. Subtract from right to left; if the top digit is smaller, borrow 1 from the column on the left — here it counts as 10. A 0 has nothing to lend: it borrows from its own left neighbour first and becomes 9.

604 − 256 = 348 →

Practice examples with answers

Solve it on paper, then open the example: the page shows the answer and the whole column.

2-digit, no regrouping

24 − 12 59 − 12 97 − 12 58 − 17 77 − 23 69 − 28 88 − 36 99 − 47

2-digit, with regrouping

31 − 12 73 − 15 71 − 17 60 − 19 70 − 23 56 − 28 92 − 34 94 − 47

3-digit numbers

210 − 105 775 − 128 386 − 172 551 − 203 841 − 239 827 − 291 756 − 354 970 − 485

Across zeros

101 − 12 604 − 256 401 − 94 200 − 76 500 − 149 800 − 268 2,000 − 136 35,801 − 12,345

Multi-digit (grade 4)

2,468 − 1,234 7,273 − 2,468 10,929 − 3,579 128,261 − 4,805 13,426 − 6,713 16,084 − 8,042 68,545 − 23,456 1,975,308 − 987,654

Common mistakes

Borrowing across a zero: the zero becomes 9, not 10. In 604 − 256 the tens pass 1 ten on to the ones and keep 9; counting them as 10 gives 358 instead of 348.
Subtracting the smaller digit from the larger one: in 86 − 39 the ones are not 9 − 6 — that gives 53 instead of 47. Borrow instead: 16 − 9.
Forgetting that the lending digit went down: in 604 − 256 the 6 hundreds became 5; leaving them at 6 gives 448 instead of 348.

Subtraction with Regrouping Calculator