How do you add and subtract mixed fractions?

You have to convert the mixed fractions to improper fractions and find a common denominator.

For example:

If you want to subtract 3/4 from 10 2/3, you have to first convert the 10 2/3 to an improper fraction, which would be 32/3. Next you have to find the common denominator for both fractions. 3 x 4 = 12, so 12 is the lowest common denominator; therefore, 3/4 = 9/12 and 32/3 = 128/12.

Now you can perform the operation:

128/12 - 9/12 = 117/12; convert 117/12 to a mixed number by dividing 117 by 12, which is 9 with a remainder of 9; 117/12 becomes 9 9/12 or 9 3/4.