Here we will discuss and show you how to figure out which number is a factor of 21, but not a multiple of 3.
The most common way to determine which number is a factor of 21, but not a multiple of 3, is to simply list the factors of 21 and the multiples of 3 so you can compare the two lists.
The answer to "Which number is a factor of 21, but not a multiple of 3?" would be all the numbers that are on the Factors of 21 list, but not on the Multiples of 3 list.
Factors of 21: 1, 3, 7, 21
Multiples of 3: 3, 6, 9, 12, 15, 18, 21...
Answer: 1, 7
Alternatively, you can figure out which number is a factor of 21, but not a multiple of 3, by dividing every factor of 21 by 3. The answer would be all the quotients that are not integers.
Factor, but not a Multiple
You can submit another "Which number is a factor, but not a multiple?" problem below.
Which number is a factor of 22, but not a multiple of 3?
Here is a similar problem in our Multiples database that we have solved for you.