Unless you are using a calculator that adds them for you, it is much harder to add fractions with uncommon denominators. Having the same denominator allows you to only have to add the numerators for your answer.
Chat with our AI personalities
You DO need a common denominator to add, subtract, or compare fractions. You DO NOT need a common denominator to multiply or divide fractions.
You need a common denominator in order to add or subtract fractions.
Common Denominator means that the denominators in two (or more) fractions are common, or the same. The common denominator is important because before you can add or subtract fractions, the fractions need to have a common denominator.Sometimes fractions have different denominators, like 2/3 and 3/4. If you want to add or subtract them, they need to have the same denominator. In order to do that, you find a common denominator which is the same thing as a common multiple, only with denominators.
The denominators must be the same before you can add or subtract fractions.
They need a common denominator when you add them. For example, if you want to add 1/2 and 1/3, you need to change the fractions to equivalents that share the same denominator, so you can combine them. 1/2 + 1/3 = 3/6 + 2/6 = 5/6