standard_description: Use measures of center and measures of variability for numerical data from random samples to draw informal comparative inferences about two populations. For example, decide whether the words in a chapter of a seventh-grade science book are generally longer than the words in a chapter of a fourth-grade science book.
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