Adding and Subtracting Fractions

Learn how to add and subtract fractions with the same and different denominators.

Adding Fractions with the Same Denominator

When fractions have the same denominator, just add the numerators and keep the denominator. For example, 1/5 + 2/5 = 3/5. Think of it like adding slices of the same pizza — if the slices are the same size, you just count how many you have.

Adding Fractions with Different Denominators

When the denominators are different, you must first find a common denominator. For example, to add 1/2 + 1/3, find the Least Common Denominator (LCD) of 2 and 3, which is 6. Convert each fraction: 1/2 = 3/6 and 1/3 = 2/6. Then add: 3/6 + 2/6 = 5/6.

Subtracting Fractions

The same rules apply. Find a common denominator first, then subtract the numerators. For 3/4 − 1/3, the LCD of 4 and 3 is 12. Convert: 3/4 = 9/12 and 1/3 = 4/12. Subtract: 9/12 − 4/12 = 5/12.