BMS Mathematics Academic Team Practice Test

To determine the Greatest Common Factor (GCF) of two numbers, we look for the largest number that divides both of them without leaving a remainder.

First, we identify the factors of each number. The factors of 12 are 1, 2, 3, 4, 6, and 12. For the number 20, the factors are 1, 2, 4, 5, 10, and 20.

Next, we find the common factors shared by both numbers. The common factors of 12 and 20 are 1, 2, and 4.

Among these common factors, 4 is the largest, which means it is the Greatest Common Factor. Thus, the GCF of 12 and 20 is indeed 4, confirming that the correct answer is 4.

In conclusion, identifying the GCF involves determining all factors of the numbers, finding the ones that are shared, and selecting the largest common factor, which in this case is 4.