3/4 + 1/6
You have to find the LCD or lowest common denominator. To add or subtract fraction the bottom must be the same number.
4 = 2 * 2
6 = 2 * 3
There is a common 2 and you need to carry the extra 2 and 3.
LCD = 2 * 2 * 3 = 12
3/4 + 1/6 =
3 * 3/12 + 1 * 2 /12 =
9/12 + 2/12 = 11/12