A Common Factor is a number that divides two or more numbers exactly.
To find the common factors of two or more numbers, first write all the factors of those numbers and then pick the common ones among them.
The factors of 6 are 1, 2, 3 and 6.
The factors of 8 are 1, 2, 4 and 8.
So, the common factors of 6 and 8 are 1, 2.
A. 1, 2, 3, and 4
B. 1, 2 and 4
C. 32, 56 and 64
D. 1, 2, 4, 5 and 10
Correct Answer: B
Step 1: 16 = 1 × 16, 2 × 8, and 4 × 4 [Write the pairs of numbers with a product of 16.]
Step 2: The factors of 16 are 1, 2, 4, 8, and 16.
Step 3: 28 = 1 × 28, 2 × 14, and 4 × 7 [Write the pairs of numbers with a product of 28.]
Step 4: The factors of 28 are 1, 2, 4, 7, 14 and 28.
Step 5: 32 = 1 × 32, 2 × 16, and 4 × 8 [Write the pairs of numbers with a product of 32.]
Step 6: The factors of 32 are 1, 2, 4, 8, 16, and 32.
Step 7: So, the common factors of 16, 28, and 32 are 1, 2, and 4.
Q1: What are the common factors of 6 and 8?
Q2: What are the common factors of 16, 28, and 32?
Q: What is the difference between a factor and a common factor?
A: A factor divides a number exactly. A common factor divides two or more numbers exactly.
Q: Is 1 always a common factor?
A: Yes, 1 is always a common factor of any set of numbers.