Finding Common Denominators Worksheet

Part 1: Multiple Choice Questions

Choose the correct answer from the options given.

1. Which of the following is a common denominator for 2/5 and 3/4?

   • a) 20
   • b) 12
   • c) 8
   • d) 15

2. What is the common denominator for 1/3 and 2/7?

   • a) 21
   • b) 10
   • c) 9
   • d) 7

3. Which of the following is the smallest common denominator for 1/2 and 2/3?

   • a) 3
   • b) 4
   • c) 6
   • d) 12

4. What is the common denominator for 1/4 and 3/5?

   • a) 20
   • b) 10
   • c) 15
   • d) 12

5. Which of the following is a common denominator for 1/6 and 5/7?

   • a) 42
   • b) 30
   • c) 21
   • d) 12

6. What is the common denominator for 2/3 and 3/4?

   • a) 12
   • b) 8
   • c) 6
   • d) 24

7. Which of the following is a common denominator for 1/3 and 2/5?

   • a) 15
   • b) 8
   • c) 10
   • d) 12

8. What is the common denominator for 1/2 and 3/4?

   • a) 8
   • b) 4
   • c) 6
   • d) 12

9. Which of the following is a common denominator for 1/5 and 2/3?

   • a) 15
   • b) 10
   • c) 5
   • d) 6

10. What is the common denominator for 1/3 and 4/7?

    • a) 21
    • b) 10
    • c) 9
    • d) 7

Part 2: True or False

Indicate whether the statement is true or false.

Part 3: Fill in the Blanks

Fill in the blanks with the correct word or phrase.

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

Part 4: Problem Solving

Solve the following problems.

1. 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?
2. 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?
3. 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?
4. 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?
5. 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?

Part 5: Essay Questions

Answer the following essay questions in complete sentences.

1. What is a common denominator? How do you find a common denominator for two or more fractions?
2. Why is it important to have a common denominator when adding or subtracting fractions? What happens if you don’t have a common denominator?
3. 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?
4. What is the least common multiple? How do you find the least common multiple of two or more numbers?
5. Give an example of a real-life situation where you might need to find a common denominator. How would you solve the problem?