Finding Common Denominators Worksheet Test

Answer the following questions by finding the common denominators.

1. Find the common denominator for 2/5 and 1/3.
2. What is the common denominator for 3/4 and 5/6?
3. Find the least common denominator for 1/2, 3/4, and 2/3.
4. What is the common denominator for 1/2, 1/3, and 1/4?
5. Find the least common denominator for 2/3, 7/8, and 5/6.
6. What is the common denominator for 1/6 and 3/8?
7. Find the least common denominator for 3/5, 2/3, and 4/7.
8. What is the common denominator for 1/5 and 2/3?
9. Find the least common denominator for 1/2, 1/3, 1/4, and 1/6.
10. What is the common denominator for 3/7 and 4/9?

Complete the following problems by finding the missing numerator or denominator.

11. 1/6 + __/18 = 5/9
12. 3/4 – __/8 = 5/16
13. __/12 + 5/6 = 7/4
14. __/15 – 1/5 = 1/3
15. 1/__ + 1/10 = 3/20

Solve the following problems by finding the common denominator and adding or subtracting.

16. 2/5 + 1/3 =
17. 5/6 – 3/4 =
18. 1/2 + 3/4 + 2/3 =
19. 1/3 – 1/4 + 2/5 =
20. 2/3 + 7/8 – 5/6 =

Simplify the following fractions by finding the common denominator.

21. 4/5 + 3/5 =
22. 2/3 + 1/6 =
23. 1/4 + 3/8 =
24. 2/5 + 7/10 =
25. 3/7 – 2/7 =

Convert the following mixed numbers into improper fractions and find the common denominator.

26. 2 1/3 + 1 1/2 =
27. 3 2/5 – 1 1/10 =
28. 4 1/6 + 2 1/3 – 3 3/4 =
29. 2 1/2 – 1 1/4 =
30. 3 3/4 + 1 2/3 =

Good Luck!