Nels needs 15 gallons of lemonade for a company picnic. If he buys the lemonade in quart bottles, how many bottles does Nels need to buy?

Ok so I know that there are 4 quarts in 1 gallon. So if there are 15 gallons, I need to multiply 15×4 to get my answer of how many quarts are in 15 gallons.  So:    15      ×     4        ______            60 quarts So Nels needs to buy 60 quarts bottles.