The skating rink rented 645 pairs of skates during the month of May. One can get this by multiplying 215 by 3. This would be 215 × 3 or 3 × 215, the order does not matter. To get the number 645.
To find how many pairs of skates did the skating rink rent during April and May, add the number of skates rented in April and the the number of skates rented in May. This would be 645 + 215. To get the number 860.
The skating rink rented 860 pairs of skates during the months of April and May.
I hope I was able to answer your question.
