When two numbers have no common factors other than 1.

In other words there is no whole number that you could divide them both by exactly (without any remainder).

21 and 22 are coprime:

• The factors of 21 are 1, 3, 7 and 21

• The factors of 22 are 1, 2, 11 and 22

(the only common factor is 1)

But 21 and 24 are NOT coprime:

• The factors of 21 are 1, 3, 7 and 21

• The factors of 24 are 1, 2, 3, 4, 6, 8, 12 and 24

(the common factors are 1 AND 3)

Also called "relatively prime" or "mutually prime".

Here we see that 12 and 16 are NOT relatively prime:

In other words there is no whole number that you could divide them both by exactly (without any remainder).

21 and 22 are coprime:

• The factors of 21 are 1, 3, 7 and 21

• The factors of 22 are 1, 2, 11 and 22

(the only common factor is 1)

But 21 and 24 are NOT coprime:

• The factors of 21 are 1, 3, 7 and 21

• The factors of 24 are 1, 2, 3, 4, 6, 8, 12 and 24

(the common factors are 1 AND 3)

Also called "relatively prime" or "mutually prime".

Here we see that 12 and 16 are NOT relatively prime:

See: Factor

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