Finding Factors and GCF

What is the GCF (Greatest Common Factor)?

• The smallest number that divides two or more numbers.

• The largest number that divides two or more numbers without leaving a remainder.

• The sum of all factors of a number.

• The product of two numbers.

What is the GCF of 5 and 15?

• 3

• 5

• 10

• 15

How do you find the GCF of two numbers?

• List the factors of each number and identify the largest factor they have in common.

• Multiply the two numbers together and divide by their sum.

• Subtract the smaller number from the larger number until you reach zero.

• Add the two numbers together and divide by two.

What is the GCF of 30 and 45?

• 10

• 12

• 15

• 20

What are factors?

• Numbers that can be added together to get another number.

• Numbers that can be multiplied together to get another number.

• Numbers that can be divided to get another number.

• Numbers that can be subtracted to get another number.

List the factors of 24.

• 1, 2, 3, 4, 6, 8, 12, 24

• 1, 2, 3, 5, 6, 12, 24

• 1, 2, 4, 8, 16

• 1, 3, 5, 7, 9, 11, 13

What is the GCF of 12 and 36?

• 6

• 12

• 18

• 24

If a number ends in 5, it is divisible by which number?

• 2

• 3

• 5

• 10

List the factors of 18.

• 1, 2, 3, 6, 9, 18

• 1, 2, 4, 6, 9

• 1, 3, 5, 9, 18

• 2, 3, 6, 12, 18

If a number ends in 0, what is it divisible by?

• 5

• 10

• 2

• 3