How do I add fractions?

When adding fractions, the denominators(the numbers at the bottom of the fractions) must be the same. If they are already the same, then you simply add the numerators (the numbers at the top of the fraction) together.

For example 2/5+1/5=3/5. Here we have added the numerators 2 and 1 to make 3. The denominators are not added together and remain the same.

If the denominators are not the same, we need to make them the same. This is done by multiplying each of them by a common factor. 

For example, if we had 2/5+1/3 we would need to make the 5 and 3 the same number. This would be done by multiplying the 5 by 3 and the 3 by 5 to make both of the denominators 15. When multiplying the denominators, we also mulitply the numerators by the same number.

So, 2x3=6 and 5x3=15 which gives up 6/15 for the first fraction. Then 1x5=5 and 3x5=15 which gives us 5/15 for the second.

This leave us with 6/15+5/15. We then add the numerators to get 11/15.