Learning to Add Fractions: Homework Help for Students

How to Do Fractions

Important Fraction Vocabulary

Fraction

A fraction is part of a whole. Fractions are usually represented with a line that divides two numbers, like 5/6, which means that there are five out of six parts of something.

Numerator

The number above the line is the numerator. In the fraction 4/5, 4 is the numerator. In other words, the numerator is the number of pieces that exist. If you cut a pizza into 6 equal slices and eat 4, you have eaten 4/6 of the whole, so the 4 is the number of pieces you ate.

Denominator

The denominator is the bottom number in a fraction. In 4/5, 5 is the denominator. This number tells you the size of the whole item you are breaking into pieces. In the pizza example, the denominator tells you how many total slices of pizza there are to begin with.

Equivalent Fractions

When two fractions are equal to the same percentage of the whole, we call them equivalent fractions. An example is 4/8 and 1/2. Dividing both the numerator and the denominator by 4 can reduce the first fraction and turn it into the second.

Adding with Common Denominators

The first type of addition you need to learn is adding fractions with the same denominators. To do this, simply add the numerators of the fractions, and carry over the denominator. For example, to add 3/8 + 2/8, add 3 and 2, and keep the denominator (8). The answers is 5/8.

Adding with Unlike Denominators

Adding fractions with uncommon denominators is a little more challenging. The first step of this process is to give the fractions a common denominator, which you can do by using equivalent fractions. Then, the fractions can be added as usual.

Example Problem

Take the example 3/4 + 3/12. Since 4 x 3 is 12, you can multiply both the numerator and denominator of the first fraction by 3 to make the denominators of both fractions the same.Since 3 x 3 = 9, the new fraction is 9/12. Now add this to the second fraction in the usual way: 9/12 + 3/12. The answer is 12/12, which can be reduced to 1.