GED Math Practice Questions: Factors and Multiples

You may encounter one or more questions on the GED Mathematical Reasoning test where you have to factor or determine multiples of two or more numbers.

These questions aren’t likely to ask you so directly to factor a number or determine its multiples. In fact, they may not even mention factors or multiples—you’ll simply need to recognize them.

Practice questions

  1. Simplify the expression,

    Square root of twenty one multiplied by the square root of fourteen.

    leaving the answer in radical form: ___________

  2. Every 3 days, we feed our anaconda. Every 14 days, we clean his cage. Today, we cleaned his cage and fed him. How many days from today will we feed him and clean his cage on the same day?

    A.28

    B.42

    C.26

    D.35

Answers and explanations

  1. The simplified expression is

    seven by the square root of six.

    To multiply square roots, you multiply the numbers inside the radicals and then simplify, but because these two numbers have obvious common factors, factoring the numbers before multiplying simplifies the process:

    Process of multiplying two square roots.

  2. 42

    You can find the answer in either of two ways:

    • Write the multiples of each number and find the first match:

      3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42

      14, 28, 42

    • Factor the numbers and multiply each factor by the greatest number of times it occurs in either number:

      two times three times seven equals forty two.