Evaluate the expressions A. 10 7/9 + (-9 2/3)
B. -10 7/10 -2 3/5
C. (4 1/2)(-3 3/10)
D. -8 3/5 divided by 1 1/5

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.

Maybe the answer is 20mm. all i really did was just multiply, which is obvious.