Lesson 5 — Activity 5: Adding and Subtracting Fractions
Completion requirements
Lesson 5 — Activity 5:
Adding and Subtracting Fractions
Fractions with the same denominator are called "like fractions." You can add and subtract like fractions easily — simply add or subtract the numerators and write the sum over the common denominator.
Let's take a look with the examples below!
Adding and Subtracting Like Fractions
Adding and Subtracting Fractions with Unlike Denominators
You have already seen how easy adding and subtracting fractions with the same or like denominators can be. You simply add or subtract the numerators and keep the same denominator, then simplify if needed. Now we are going to talk about adding fractions with different denominators.
When adding fractions with different denominators, the denominators must be equal. So we must complete this step first. In order to do this, we have to find the lowest or least common denominator or lowest common multiple — in other words, the denominators must be the same. The lowest common denominator is the smallest of all the possible denominators.
So how do we find the lowest common denominator? We need to find the multiples of each denominator and then find the smallest number that is the same.
Let's look at one more example!
Click on the Play button below to watch a video on how to add and subtract fractions with unlike denominators.
Self-check!
Try these questions!
Answer these questions on your own first.
When you are finished, click on the tab below to check your answers!
Addition and Subtraction Practice!
Extra Practice!
Click here to download extra practice questions for adding fractions! Complete the questions, and then click here to check your answers.