What two numbers have a GCF of 20?

Here we will explain and show you how to find what two numbers have the Greatest Common Factor (GCF) of 20.

There is actually an infinite number of answers to this question. First, note that both the numbers we are looking for must be multiples of 20. Below is the beginning list of multiples of 20 (1 through 7) in numerical order.

1. 20
2. 40
3. 60
4. 80
5. 100
6. 120
7. 140
etc...

Two numbers that have a GCF of 20 can be 20 and any other number on the list above. Thus, two numbers that have a GCF of 20 are:

20 & 40
20 & 60
20 & 80
etc...

That is not all! Any combination of any multiple of 20 and "odd" multiples of 20 will also have GCF of 20. We numbered the multiples above so it would be easy to identify the "odd" multiples (number 1, 3, 5, 7, etc). Thus, here are some more examples of two numbers that also have a GCF of 20.

40 & 60
40 & 100
80 & 100
80 & 140
etc...

Like we stated above, there are infinite combinations of two numbers whose GCF is 20. The lists we created can go on forever.

Two numbers have a GCF of Calculator
Need the answer to a similar problem? Enter your GCF below to find the two numbers with that GCF.

Teacher Tip: If you are a teacher, you could ask these questions of your students: "I am thinking of two numbers and the GCF is 20, what are the numbers?" or "What are two numbers whose GCF is 20?"

What two numbers have a GCF of 21?
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