Subtracting fractions word problems

Subtracting fractions word problems arise in many situations. Let's consider some examples. Before you study this lesson, I strongly recommend that you take a look at comparing fractions  or  comparing fractions calculator.

As shown in the word problem above, we usually subtract the smaller fraction from the bigger fraction when doing word problems involving the subtraction of fractions. Therefore, an understanding of how to subtract fractions is important.

For instance, 1/2 is smaller than 2/3, so you will do 2/3 - 1/2

Subtracting fractions word problems: 4 real-life examples.

Example #1:
A recipe needs 3/4 teaspoon black pepper and 1/4 teaspoon red pepper. How much more black pepper does the recipe need?

This fraction word problem requires subtraction.

Solution:

The fact that the problem is asking how much more black pepper the recipe needs is an indication that 3/4 is bigger than 1/4.

However, it does not hurt to check!

3/4 - 1/4 = 2/4 = 1/2

The black pepper is 1/2 of a teaspoon more than the red pepper.

Example #2:
A football player advances 2/3 of a yard. A second player in the same team advances 5/4 of a yard. How much more yard did the second player advance?

Again, we need to perform subtraction to solve this problem.

Solution

5/4 - 2/3 = 15/12 - 8/12 = 7/12

6/12 is equal to 1/2, so 7/12 is just a bit more than half.

So, the second player advanced by about half of a yard more.

To be more precise though, you can say that the second player advanced by 7/12 of a yard more than the first player.

Example #3:
John lives 3/8 mile from the Museum of Science. Sylvia leaves 1/4 mile from the Museum of Science. How much closer is Sylvia from the museum?

Solution

The fact that the word problem is saying how much closer Sylvia is, is an indication that 1/4 is smaller than 3/8.

3/8 - 1/4 = 3/8 - 2/8 = 1/8

Sylvia is closer to the library by 1/8 mile.

You can also say that John is further away by 1/8 mile.

Example #4:
Maria caught shrimp that weighted 4 2/3 pounds. If she gave 3 1/6 pounds to his friends, how much shrimp did she have left?

Solution

In order to find out how much shrimp Maria is left with, we need to do the following subtraction.

4 2/3 - 3 1/6

4 2/3 - 3 1/6 = (4 - 3) + (2/3 - 1/6)

4 2/3 - 3 1/6 = 1 + (4/6 - 1/6)

4 2/3 - 3 1/6 = 1 + (3/6)

4 2/3 - 3 1/6 = 1 3/6 = 1 1/2

Maria has 1 1/2 pounds of shrimp left.