Lesson 2: Equivalence with Customary Units of Capacity

Property

The customary system uses specific units to measure capacity, which is the amount a container can hold.

Property

To solve word problems involving customary units of capacity, use the following conversion factors:

• 1 gallon ($gal$) = 4 quarts ($qt$)
• 1 quart ($qt$) = 2 pints ($pt$)
• 1 pint ($pt$) = 2 cups ($c$)
• 1 cup ($c$) = 8 fluid ounces ($fl$ $oz$)

Examples

• A recipe for lemonade requires 3 quarts of water. How many pints of water are needed?

• A water cooler holds 5 gallons of water. If students have already drunk 8 quarts, how many quarts of water are left?

Explanation

Solving word problems with customary units of capacity often involves converting between units to compare quantities or find a total. First, identify the units given in the problem and the unit required for the answer. Then, use the appropriate conversion factor to change the units, remembering to multiply when converting from a larger unit to a smaller one. Finally, perform any necessary calculations like addition or subtraction to solve the problem.