Subtraction

Subtract Two-Digit Numbers With Borrowing

Subtract 28 from 63. The ones column (3 - 8) requires borrowing 1 ten from the tens column, turning 3 into 13 before subtracting.

Example

Subtract 28 from 63 by regrouping one ten. When a column's top digit is smaller than the one below it, we borrow: one ten from the next column becomes ten ones, making the subtraction possible. Regrouping does not change the number's value, it only rewrites it so each column has enough to subtract from.

highlighted = computed this step

Step 1 — Set up

Line up the numbers by place value.

xxxx63−28x□□\begin{array}{rrr}\phantom{x}&\phantom{x}&\phantom{x}\\\phantom{x}&6&3\\-&2&8\\\hline\\\phantom{x}&\square&\square\end{array}
Line up 63 and 28 by placetens62ones38-63 - 28Start in the ones column.

Step 2 — Borrow for ones

Ones: 3 < 8, borrow 1 ten: 13 - 8 = 5.

x513x63−28x□5\begin{array}{rrr}\phantom{x}&\hl{5}&\hl{13}\\\phantom{x}&6&3\\-&2&8\\\hline\\\phantom{x}&\square&\hl{5}\end{array}
Ones: 3 is less than 8, borrow 1 tentens562ones13385-1 ten = 10 ones3 ones + 10= 13 ones13 - 8 = 5 ones1 ten becomes 10 ones, so 3 ones become 13 ones.

Step 3 — Tens column

Tens: 5 - 2 = 3, write 3.

x513x63−28x35\begin{array}{rrr}\phantom{x}&5&13\\\phantom{x}&6&3\\-&2&8\\\hline\\\phantom{x}&\hl{3}&5\end{array}
Tens: 5 - 2 = 3tens5623ones1338-1 ten = 10 ones3 ones + 10= 13 ones5 - 2 = 3 tensThe tens column is now 5 - 2.

Step 4 — Result

Read the complete difference: 35.

x513x63−28x35\begin{array}{rrr}\phantom{x}&5&13\\\phantom{x}&6&3\\-&2&8\\\hline\\\phantom{x}&3&5\end{array}
63 - 28 = 35tens5623ones13385-1 ten = 10 ones3 ones + 10= 13 ones3 tens and 5 ones make 35Put the tens and ones digits together to read the difference.
borrowing When a digit in the minuend is too small to subtract from, borrow 1 from the column to its left. The left column decreases by 1 and the current column increases by 10, making subtraction possible.