How to Split Up a Pizza into Unequal Amounts

You may have to add or subtract fractions in word problems that involve splitting up part of a whole into unequal amounts. For example, consider the following pizza problem:

Joan ate 1/6 of a pizza, Tony ate 1/4, and Sylvia ate 1/3. What fraction of the pizza was left when they were finished?

In this problem, just jot down the information that’s given as word equations:


These fractions are part of one total pizza. To solve the problem, you need to find out how much all three people ate, so form the following word equation:

All three = Joan + Tony + Sylvia

Now you can substitute as follows:


There are several ways to add these fractions. For example:


However, the question asks what fraction of the pizza was left after they finished, so you have to subtract that amount from the whole:


Thus, the three people left 1/4 of a pizza.