Add and subtract the following fractions. Remember to find the LCD first. 1. 1/2 + 1/3
2. 1/6 + 1/8 + 1/3
3. 4/11 + 5/22 + 3/44
4. 3/4 - 3/8
5. 11/15 - 3/5

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.