standard_description: Compute unit rates associated with ratios of fractions, including ratios of lengths, areas and other quantities measured in like or different units. For example, if a person walks 1/2 mile in each 1/4 hour, compute the unit rate as the complex fraction 1/2/1/4 miles per hour, equivalently 2 miles per hour.
problem_activity: Two expressions are given below.
Expression A:
$${5q-r}$$
Expression B:
$${ -2q+3r-4}$$
a.   Write a simplified expression that represents A + B.
b.   Write a simplified expression that represents A - B.


aligns: no