Two numbers having only 1 as a common factor are called ____ numbers.
coprime
Idea: Two numbers are coprime if the only factor they both share is 1.
How to understand:
Symbol way (small steps):
We say their HCF (or GCD) is 1.
\( \text{HCF}(a,b) = 1 \)
\( \Rightarrow a \text{ and } b \text{ are coprime} \)
Example: 8 and 15
Factors of 8: 1, 2, 4, 8
Factors of 15: 1, 3, 5, 15
Common factors: 1
So, \( \text{HCF}(8,15) = 1 \)
Therefore, 8 and 15 are coprime.
Important note: Coprime does not mean “both are prime”.
Example: 14 and 25 are coprime.
\( \text{HCF}(14,25) = 1 \)
But 14 and 25 are not prime numbers.