how do I convert (reduce) 21 pints to its smallest number of larger units?

Answer 1

lets see...

with two cups to the pint, and two pints to the quart, and four quarts to the gallon..

looks like a pint is an eighth of a gallon, so you have two gallons (16 pints) and you will have two quarts, and one pint left over.

2gal 2qt 1pt