Answer:
When two numbers have no common factors other than 1.
Step-by-step explanation:
In other words there is no value that you could divide them both by exactly (without any remainder).
21 and 22 are relatively prime:
• 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 relatively prime:
• 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)
Relatively Prime is also called "coprime" or "mutually prime".
Here we see that 12 and 16 are NOT relatively prime