What is the GCD of 15 and 25?

To determine the greatest common divisor (GCD) of 15 and 25, we first need to consider the factors of each number.

The factors of 15 are 1, 3, 5, and 15.

The factors of 25 are 1, 5, and 25.

Next, we look for the largest factor that both numbers share. From the list, we can see that the number 5 is the highest factor that appears in both lists. This means that 5 is the greatest common divisor of 15 and 25.

Understanding the concept of GCD is important; it identifies the largest possible number that divides both of the given numbers without leaving a remainder. In this case, since 5 divides both 15 (as 15 ÷ 5 = 3) and 25 (as 25 ÷ 5 = 5), it confirms that 5 is indeed the greatest common divisor. Hence, this answer is supported by the factorization and division validation of the two numbers involved.