Adding fractions is another mathematical skill your child will start to learn around fourth grade along with learning how to multiply fractions. When learning how to add fractions, your student will also learn about least common denominators, or least common multiples. Dive into our resources to get started, or scroll below to see some adding fractions basics.
Adding Fractions Basics
Adding fractions can be a little difficult because in order to add fractions together, their denominators have to be the same. By first finding a common denominator or multiple, the fractions can then be added together using some general rules.
Find a common denominator using the least common denominator method
Add the numerators and put the sum over the common denominator
Simplify if needed
Least Common Denominator Method
Let’s look at 1⁄4 + 5⁄6 :
Find the least common multiple between 4 and 6. We can find multiples of a number by multiplying it by another number other than 0. The first three multiples of 4 are 4, 8, and 12, while the first three multiples of 6 are 6, 12, and 18. The smallest number that is a multiple between the two (the least common multiple) is 12.
Once you have found a least common multiple to use as the least common denominator, multiply the denominator and numerator of each fraction by a number so that the denominator becomes the common denominator and the numerator changes to create equivalent fractions: 1⁄4 x 3⁄3 = 3⁄12, 5⁄6 x 2⁄2 = 10⁄12
Continue to follow the rest of the general rules:
3⁄12 + 10⁄12 = 13⁄12 = 1 1⁄12
Another way of finding a common denominator is to multiply the two denominators by each other. However, this will not necessarily give you the smallest common denominator to work with and can sometimes make your fractions look messy.
Now that you have a basic set of rules to follow when adding fractions, use our worksheets and exercises to practice!