Subtract a one-digit number from a three-digit number: step-by-step example
30 October 2026
If your child is learning to subtract a one-digit number from a three-digit number, it helps to break the process into small, clear steps. This example shows exactly how to handle a calculation where borrowing is needed, making it easy for children to follow along.
Worked example
Question: 324 - 7
Step 1: Look at the ones column. 4 - 7 is not possible, so we need to exchange (borrow) from the tens.
Step 2: Take 1 ten from the tens column. Now, the tens column has 1 less ten, and the ones column becomes 14.
Step 3: Now subtract 7 from 14. 14 - 7 = 7.
Step 4: Move to the tens column. After borrowing, there are 1 ten left. 1 ten minus 0 tens = 1 ten.
Step 5: The hundreds column stays the same: 3 hundreds.
So, 324 - 7 = 317.
After seeing this example, your child will know what to do when the ones column is too small to subtract from. They will recognise when to exchange from the tens and how to finish the calculation. Now, they can try similar questions to build confidence with this type of subtraction.
