Exploring Common Denominators with Example Problems

What is a common denominator?

• A number that is the same in the numerators of two fractions

• A number that is the same in the whole numbers of two fractions

• A number that is the same in the mixed numbers of two fractions

• A number that is the same in the denominators of two fractions

What are factors?

• Numbers that can be divided by another number

• Numbers that can be multiplied to get another number

• Numbers that are always even

• Numbers that are always prime

Which of the following is a factor of 8?

• 7

• 4

• 5

• 3

How many times does 4 go into 8?

• 1 time

• 2 times

• 4 times

• 3 times

What is the common denominator of 1/4 and 3/8?

• 4

• 8

• 12

• 16

What do you multiply 1/4 by to get a common denominator with 3/8?

• 1/1

• 2/2

• 3/3

• 4/4

How many times does 5 go into 15?

• 2 times

• 1 time

• 4 times

• 3 times

What is the common denominator of 2/5 and 3/15?

• 10

• 5

• 20

• 15

How many times does 9 go into 90?

• 5 times

• 10 times

• 8 times

• 9 times

What is the common denominator of 9/90 and 40/90?

• 9

• 40

• 100

• 90