Question

The ___ of the 2 numbers is the greatest number that divides both the numbers exactly.

Answer 1

The Highest Common Factor (H.C.F) of two (or more) numbers is the largest number that divides both the numbers exactly.
Example:
Factors of 12: 1, 2, 3, 4, 6, 12
Factors of 18: 1, 2, 3, 6, 9, 18
Common factors of 12 and 18 = 1, 2, 3, 6
The highest common factor of 12 and 18 = 6
Therefore 6 is the highest number that divides 12 and 18 exactly.