How Do You Subtract Two Fractions with Different Denominators?

Note:

In order to subtract fractions, they must have the same denominators. To get the same denominators, you can find equivalent fractions! This tutorial shows you how to subtract fractions with unlike denominators.

Keywords:

example
practice
subtract
subtraction
different denominators
unlike denominator
fraction
equivalent fractions
common denominator

Background Tutorials

Explain why a fraction a/b is equivalent to a fraction (n × a)/(n × b) by using visual fraction models, with attention to how the number and size of the parts differ even though the two fractions themselves are the same size. Use this principle to recognize and generate equivalent fractions.
- What are Equivalent Fractions?
  
  Finding equivalent fractions is an important part of things like adding, subtracting, and comparing fractions. But what are they? In this tutorial, you'll learn that equivalent fractions are just fractions that have the same value, even though they may look very different! Take a look at equivalent fractions by watching this tutorial!
Compare two fractions with different numerators and different denominators, e.g., by creating common denominators or numerators, or by comparing to a benchmark fraction such as 1/2. Recognize that comparisons are valid only when the two fractions refer to the same whole. Record the results of comparisons with symbols >, =, or <, and justify the conclusions, e.g., by using a visual fraction model.
- How Do You Find a Common Denominator and a Least Common Denominator?
  
  This tutorial gives you some practice finding a common denominator and the least common denominator of three fractions. There's only one least common denominator, but there are many common denominators. This tutorial gives you one. Can you find another?
Solve word problems involving addition and subtraction of fractions referring to the same whole and having like denominators, e.g., by using visual fraction models and equations to represent the problem.
- How Do You Subtract Two Fractions with the Same Denominator?
  
  To subtract fractions with the same denominators, just subtract the numerators! Follow along with this tutorial to see an example of subtracting fraction with the same denominators.