Decimal Subtraction

Decimal subtraction

Decimal subtraction works the same way as whole-number subtraction, but place value must stay aligned. The goal is to subtract exactly and simplify the result.

1) Line up the decimal points

Write the numbers so the decimal points are directly above one another. If needed, add trailing zeros so both numbers have the same number of decimal places. For example, treat 4.5 as 4.50 when subtracting from 7.32.

2) Subtract from right to left

Start in the far-right column and work leftward, borrowing when a digit in the top number is smaller than the digit below it. Keep each borrowed value in the correct place value.

3) Place the decimal point in the answer

The decimal point in the result goes straight below the aligned decimal points in the problem.

4) Simplify the final answer

Remove unnecessary trailing zeros after the decimal point if the result still stays exact. For example, 3.40 can be written as 3.4.

Check your work

Add your answer to the number subtracted. If the sum matches the original starting number, your subtraction is correct.

This method helps you avoid place-value errors and gives an exact result every time.