Subtraction with Regrouping: 101 − 12

Subtraction with Regrouping Calculator
Minuend
Subtrahend

What is 101 − 12?

Answer

101 − 12 =
89

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

101 − 12 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.
09+10
1(was 1, now 0)0(was 0, now 9)1 (was 1, now 11)
−12
89

Column by column: 101 − 12

  • Ones: 1 is less than 2 — borrow 1 hundred across the zero: hundreds 1 → 0, tens 0 → 9; 11 − 2 = 9 — write 9.
  • Tens: after borrowing, 9; 9 − 1 = 8 — write 8.
  • Hundreds: after borrowing, 0 — a leading zero is not written.

101 − 12 = 89

Second check: 101 − 89 = 12

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FAQ

What is 101 − 12?

101 − 12 = 89

How do you check that 101 − 12 = 89?

Add the difference and the subtrahend: 89 + 12 = 101. Getting the minuend back means the difference is right.

How many times do you borrow in 101 − 12?

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

Why does 0 become 9 when borrowing in 101 − 12?

The zero has nothing to lend, so it first borrows 1 from its left neighbour and becomes 10; then it lends 1 to the column on its right and keeps 9.