Question

The gardener used 20 quarts of water on his rose bed. How many gallons of water did the gardener use? (1 gallon = 4 quarts)

Answer 1

The only thing you need to do is
20 divide by 4 = 5 gallons of water used

Answer 2

5 gallons

4qts = 1 gal
8qts = 2 gal
12qts=3 gal
16qts=4 gal
20qts=5 gal