US Customary units of weight review (oz & lb)

CCSS Math: 4.MD.A.1, 5.MD.A.1
Review the size of ounces and pounds and how to convert between the two.  Then, try some practice problems.

Customary units of weight

Weight is a quantity of heaviness. For example, you are measuring the weight of your body when you step on to a scale.
In the customary system of measurement, the most common units of weight are the ounce (oz) and pound (lb).

How much is an ounce?

A slice of bread has a weight of about 11 ounce:

How much is a pound?

A soccer ball has a weight of about 11 pound:
Want to learn more about customary units of weight? Check out this video.

Practice set 1: Estimating weight

Problem 1A
Identify the most reasonable unit to measure the weight of a refrigerator.
Choose 1 answer:
Choose 1 answer:

Want to try more problems like this? Check out this exercise.

Converting pounds to ounces

1 pound=16 ounces1 \text{ pound} = \green{16}\text{ ounces}
To convert pounds to ounces we multiply the number of pounds by 16\greenD{16}.
30 pounds=30×16=480 ounces\pink{30} \text{ pounds}= \pink{30}\times\green{16}=\blue{480}\text{ ounces}

Converting ounces to pounds

1 ounce=116 pound1\text{ ounce}= \dfrac1{\green{16}} \text{ pound}
To convert ounces to pounds we divide the number of ounces by 16\greenD{16}.
112 ounces=11216=112÷16=7 pounds\pink{112} \text{ ounces}= \dfrac{\pink{112}}{\green{16}}=\pink{112}\div\green{16}=\blue7\text{ pounds}
Want to learn more about converting pounds to ounces? Check out this video.

Practice set 2: Converting units of weight

Problem 2A
99 pounds ==
  • Your answer should be
  • an integer, like 66
  • an exact decimal, like 0.750.75
  • a simplified proper fraction, like 3/53/5
  • a simplified improper fraction, like 7/47/4
  • a mixed number, like 1 3/41\ 3/4

Want to try more problems like this? Check out these exercises:
Convert larger units to smaller units
Converting between units