Adding and Subtracting Fractions with Unlike Denominators – Worksheets with Answers

Download these free, printable PDF worksheets for adding and subtracting fractions with unlike denominators, complete with answer keys.

Each problem involves adding or subtracting fractions with unlike denominators. Students are given horizontal space to rewrite and solve the expressions using the least common multiple and to simplify the result. The worksheets help students practice manipulating fractions using common denominators to perform the required operation.

These printable PDF fraction worksheets work well for independent practice, classroom work, or homeschool instruction. Ideal for grades 4-6, the activities reinforce essential arithmetic skills, and strengthen understanding of fractional parts. Each worksheet printable includes an answer key on the second page for quick and easy grading.

Check out our complete Fraction Addition and Subtraction Workbook on Teachers Pay Teachers for even more practice pages!

Worksheet 1 Worksheet 2

To add or subtract fractions, the denominators must be the same. If the fractions have different denominators, then one or both of the fractions will need to be converted into an equivalent fraction so that they share a common denominator.

First, you need to find which denominator should be used, usually by finding the LCM (least common multiple) of the original denominators. The new denominator is called the common denominator. (If you use the LCM of the original ones, it is specifically called the least common denominator, because it’s the smallest denominator that will work.)

Next, rewrite the fraction expression with equivalent fractions using the new common denominator for each one.

Then add (or subtract) the fractions as usual, since the denominators are the same.

The example below is from a page of the workbook Mastering Fractions with Factors and Multiples.