Subtraction with Regrouping: 170 − 78

Subtraction with Regrouping Calculator
Minuend
Subtrahend

What is 170 − 78?

Answer

170 − 78 =
92

With regrouping: 2 borrows — from the tens and the hundreds

170 − 78 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.
016+10
1(was 1, now 0)7(was 7, now 16)0 (was 0, now 10)
−78
92

Column by column: 170 − 78

  • Ones: 0 is less than 8 — borrow 1 ten: tens 7 → 6; 10 − 8 = 2 — write 2.
  • Tens: after borrowing, 6; 6 is less than 7 — borrow 1 hundred: hundreds 1 → 0; 16 − 7 = 9 — write 9.
  • Hundreds: after borrowing, 0 — a leading zero is not written.

170 − 78 = 92

Second check: 170 − 92 = 78

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See Also

FAQ

What is 170 − 78?

170 − 78 = 92

How do you check that 170 − 78 = 92?

Add the difference and the subtrahend: 92 + 78 = 170. Getting the minuend back means the difference is right.

How many times do you borrow in 170 − 78?

2 borrows: each time the top digit was smaller than the one below it, 1 was borrowed from the column on the left.