How do you add improper fractions?

To add improper fractions, determine if they have the same denominator, add the numerators, write the new numerator over the denominator, and simplify the answer, if necessary.

1. Find the same denominator

   Check that the improper fractions have the same denominator before you attempt to add them. If they have the same denominator, add the numerators. If they do not have the same denominator, find the least common multiple that the two numbers share. Write that number as the new denominator.

2. Add the numerators

   Multiply each numerator with the number that equals the least common denominator when multiplied with the old denominator. For a least common denominator of 12 and an improper fraction of 4/3, multiply the 4 with 3 because 3 x 4 is equal to 12. The new fraction is 16/12. Add the new numerators, and write the result over the new denominator.

3. Simplify the answer

   If necessary, simplify the resulting fraction, and convert it to a mixed fraction, if needed. Given the problem 4/3 + 5/4, the least common denominator is equal to 12. The new fractions are 16/12 + 15/12, which is equal to 31/12. Although the answer can't be simplified, it can be converted to a mixed fraction of 2 7/12.