Subtraction with Regrouping: 123 − 45

Subtraction with Regrouping Calculator

What is 123 − 45?

Answer

123 − 45 =

78

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

123 − 45 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.
		0	11	+10
		1(was 1, now 0)	2(was 2, now 11)	3 (was 3, now 13)
	−		4	5
			7	8

Column by column: 123 − 45

Ones: 3 is less than 5 — borrow 1 ten: tens 2 → 1; 13 − 5 = 8 — write 8.
Tens: after borrowing, 1; 1 is less than 4 — borrow 1 hundred: hundreds 1 → 0; 11 − 4 = 7 — write 7.
Hundreds: after borrowing, 0 — a leading zero is not written.

123 − 45 = 78

Second check: 123 − 78 = 45

Similar examples to practise

Related Calculations

78 + 45 = 123 - Addition with Regrouping

See Also

Addition with Regrouping Calculator - Column addition step by step, with every carry
Long Division Calculator - Step-by-step long division with detailed explanation
Long Multiplication Calculator - Column multiplication with partial products, step by step
Subtracting Fractions Calculator - Subtract fractions, mixed numbers and whole numbers step by step

Recalculate with different values ↑

Column subtractions of 45

Example	Difference
97 − 45	52
99 − 45	54
103 − 45	58
108 − 45	63
110 − 45	65
112 − 45	67
114 − 45	69
116 − 45	71
119 − 45	74
121 − 45	76
123 − 45	78
128 − 45	83
130 − 45	85
134 − 45	89
137 − 45	92
139 − 45	94
143 − 45	98
150 − 45	105
181 − 45	136
217 − 45	172

FAQ

What is 123 − 45?

123 − 45 = 78

How do you check that 123 − 45 = 78?

Add the difference and the subtrahend: 78 + 45 = 123. Getting the minuend back means the difference is right.

How many times do you borrow in 123 − 45?

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

See Also