Practice Math Questions for Praxis: Measurements and Conversions

By Carla Kirkland, Chan Cleveland

The Praxis Core exam will contain some questions where you have to convert measurements to different units. Of course, as you’ll see in the following practice questions, you’ll probably have to do some extra work to find the right answer.

The first question requires you to do some metric conversion before you figure out how much of a chemical remains in a drum, while the second one asks you to convert units and then do some simple multiplication.

Practice questions

  1. Dr. Richard has 5.382 kiloliters of a chemical in a drum. He pours out 42.79 hectoliters of the chemical. How much of the chemical remains in the drum?

    A. 48.172 kL
    B. 1.103 kL
    C. 4.8172 kL
    D. 4.9541 kL
    E. 374.08 kL

  2. How many gallons are in 4.5 cups?

    A. 0.28125
    B. 3.56
    C. 20.5
    D. 72
    E. 11.5

Answers and explanations

  1. The correct answer is Choice (B).
    The choices are in kiloliters, so convert 42.79 hectoliters to kiloliters. The number of kiloliters in a volume is less than the number of hectoliters, so move the decimal point to the left. Kilo- and hecto- are one place apart on the metric prefix chart, so move the decimal point one place to the left. The result is 4.279 kiloliters. Next, subtract 4.279 from 5.382. You can use your calculator.

    5.382 – 4.279 = 1.103

    What remains in the drum is 1.103 kiloliters of the chemical.

  2. The correct answer is Choice (A).

    You’re looking for a number of gallons here, so work with gallons. A cup is 1/16 of a gallon, so replace “cups” with “1/16 gallon”: