Subtract Mixed Numbers

Subtracting mixed numbers

Mixed numbers combine a whole number and a fraction, such as (3\tfrac{1}{2}). When subtracting them, the main goal is to make sure the fractional parts can be subtracted correctly.

1) Check the fractional parts

If the top fraction is smaller than the fraction you are subtracting, you need to borrow 1 whole from the whole-number part. That 1 whole becomes a fraction with the same denominator as the mixed numbers.

2) Subtract the fractions and whole numbers

After borrowing if needed, subtract the fractional parts first, then the whole numbers. Keep the denominator the same when subtracting fractions with like denominators.

3) Simplify the result

Write the answer as a mixed number in simplest form. Reduce the fraction if possible.

Example method

For a problem like (5\tfrac{1}{4} - 2\tfrac{3}{4}), the fractional part is too small, so borrow 1 from 5. Then subtract carefully and simplify.

Quick check

Add your answer to the number you subtracted. You should get the original mixed number. This is a good way to see whether your subtraction is correct.