How do you add fractions to other fractions?

Answer 1

If the denominators (bottom numbers) are the same, add the numerators together, and the denominator stays the same.

Example: 1/5 + 3/5 = 4/5

If the denominators are not the same, you have to find a common denominator, then change the fractions to equivalent fractions having that denominator. This is where the principle of the Least Common Denominator comes in. Once the two fractions have the same denominator, you can add them, as above, and simplify if possible.

Example 1: 1/2 + 1/3 = 5/6

By multiplying both the numerator and denominator by the same number, you can create an equivalent fraction: 1/2 x 3/3 = 3/6, which is the same as 1/2.

The same denominator can be formed by multiplying 1/3 x 2/2 = 2/6, which is the same as 1/3.

Now you add 1/2 + 1/3 = 3/6 + 2/6 = 5/6

Example 2 : 1/4 and 1/12 = 1/3

The LCD is 12, so you can just make 1/4 equal to 3/12 (using 3/3).

Then add:

1/4 + 1/6 = 3/12 + 1/12 = 4/12 which simplifies (divide by 4/4) to 1/3.