How to Subtract Fractions Step by Step

Subtracting fractions works almost exactly like adding fractions. Before you subtract, both fractions need to use the same size pieces.

Quick idea

Make the denominators match, subtract only the numerators, and keep the denominator unchanged.

Steps

1. Check whether the denominators already match.
2. If they do not match, find a common denominator.
3. Rewrite both fractions using equivalent fractions.
4. Subtract the numerators and simplify the result.

Worked example

Subtract one third from five sixths.

Full solution

Step-by-step walkthrough

Step 1

The denominators are 6 and 3. Use 6 as the common denominator.

Step 2

One third is the same as two sixths.

Step 3

Subtract 2 from 5 to get 3 sixths, then simplify to one half.

Common mistake

The denominator tells the size of the pieces, so it does not get subtracted. Only the numerators are subtracted after the denominators match.

Practice problems

1. Subtract 3/4 - 1/4.
2. Subtract 5/6 - 1/2.
3. Subtract 7/8 - 1/4.

Answers

1. 1/2
2. 1/3
3. 5/8

Ask Pennpaper to explain it live

If the steps make sense but you still feel stuck, start a Pennpaper lesson and ask the tutor to draw the problem on the whiteboard. Seeing the symbols move step by step is often what makes the concept click.

Related guides

• How to Add Fractions With Unlike Denominators
• How to Divide Fractions: Keep, Change, Flip
• How to Solve Fraction Word Problems