A. We simply have to add 1,200 people to the 18, 500 or subtract 1,200 from 18, 500 people.
So, the equations are:


B. The step to solving this problem is simply to add or subtract 1,200 from 18, 500.


C. The maximum number of people the sports arena can hold is 19, 700 people.
D. The minimum number of people the sports arena can hold is 17, 300 people.