How do you subtract unlike denominators?

Answer 1

Change them so they have like denominators. Multiply all that fractions by the least common denominator so that they'll have the same denominators.

Example: 1/2 - 1/3

Step 1: The least common denominator is 6.

Step 2: Change each fraction so their denominator is 6 (You'll get 3/6 and 2/6)

Step 3: Subtract them: 3/6 - 2/6 = 1/6

Answer 2

To subtract unlike denominators, you must first find the common denominator of the two fractions. For example, if:

3/4 - 1/8 =

you would see that 4 is a factor of 8. To make the denominators the same, you would simply multiply 3/4 by 2/2 because 2 times 4 is 8. Like so:

6/8 - 1/8 = 5/8

Now you have the same denominator. 6/8 is the same as 3/4, except the fact that 3/4 is just the simplified version.

Voila!

However, notice: When changing a fraction to have a common denominator, multiply the numerator the same as the denominator.