Date: May 14, 2023

Finding Common Denominators Worksheet

Part 1: Multiple Choice Questions

Choose the correct answer from the options given.

Which of the following is a common denominator for 2/5 and 3/4?
- a) 20
- b) 12
- c) 8
- d) 15
What is the common denominator for 1/3 and 2/7?
- a) 21
- b) 10
- c) 9
- d) 7
Which of the following is the smallest common denominator for 1/2 and 2/3?
- a) 3
- b) 4
- c) 6
- d) 12
What is the common denominator for 1/4 and 3/5?
- a) 20
- b) 10
- c) 15
- d) 12
Which of the following is a common denominator for 1/6 and 5/7?
- a) 42
- b) 30
- c) 21
- d) 12
What is the common denominator for 2/3 and 3/4?
- a) 12
- b) 8
- c) 6
- d) 24
Which of the following is a common denominator for 1/3 and 2/5?
- a) 15
- b) 8
- c) 10
- d) 12
What is the common denominator for 1/2 and 3/4?
- a) 8
- b) 4
- c) 6
- d) 12
Which of the following is a common denominator for 1/5 and 2/3?
- a) 15
- b) 10
- c) 5
- d) 6
What is the common denominator for 1/3 and 4/7?
- a) 21
- b) 10
- c) 9
- d) 7

Indicate whether the statement is true or false.

Statement	True or False
A common denominator is a multiple of the denominators of two or more fractions.
To find a common denominator, you need to find the least common multiple of the denominators.
When adding or subtracting fractions, you need to have the same denominator.
You can always find a common denominator for any two fractions.
When finding a common denominator, you only need to consider the denominators of the fractions.

Fill in the blanks with the correct word or phrase.

To add or subtract fractions, you need to find a ____ denominator.
A common denominator is a multiple of the ____ of the fractions’ denominators.
The least common multiple is also known as the ____ common multiple.
To find the least common multiple, you need to list the ____ of each number and find their common factors.
When adding or subtracting fractions, you need to have the same ____.

Solve the following problems.

Rachel has 2/5 of a pizza left, and John has 3/4 of a pizza left. What is the smallest amount of pizza they can have if they want to split it evenly?
If 3/4 of a class are boys and 5/6 of the boys have brown hair, what fraction of the class are boys with brown hair?
A recipe calls for 1/2 cup of sugar and 3/4 cup of flour. What is the smallest amount of each ingredient you can measure out if you want to make 3 batches of the recipe?
If a tank can hold 3/5 of a gallon of water and another tank can hold 1/2 of a gallon of water, what is the smallest amount of water you can measure out if you want to fill both tanks equally?
A group of friends order 2/3 of a large pizza and 1/4 of a small pizza. What is the smallest amount of pizza they can have if they want to split it evenly?

Answer the following essay questions in complete sentences.

What is a common denominator? How do you find a common denominator for two or more fractions?
Why is it important to have a common denominator when adding or subtracting fractions? What happens if you don’t have a common denominator?
Can you always find a common denominator for any two fractions? Why or why not? What is the easiest way to find a common denominator?
What is the least common multiple? How do you find the least common multiple of two or more numbers?
Give an example of a real-life situation where you might need to find a common denominator. How would you solve the problem?