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Least Common Denominator Worksheet

Practice finding the least common denominator (LCD) for fractions and using it to compare and add fractions.

Grade 7 Math FractionsLeast Common Denominator
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Includes

Fill in the Blanks3 Short AnswerMultiple Choice

Standards

CCSS.MATH.CONTENT.6.NS.B.4CCSS.MATH.CONTENT.7.NS.A.1

Topics

mathfractionsLCDleast common denominatorgrade 7
7 sections · Free to use · Printable
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Least Common Denominator (LCD) Practice

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Date:

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Read each question carefully and answer to the best of your ability. Show all your work for full credit.

1. The Least Common Denominator (LCD) of two or more fractions is the   common multiple of their denominators.

2. To find the LCD, you can list the   of each denominator until you find the smallest number that appears in all lists.

3. The LCD is essential for   and   fractions with different denominators.

Find the Least Common Denominator (LCD) for each pair of fractions.

4. 1/3 and 1/5

5. 2/4 and 3/6

6. 3/8 and 5/12

7. 1/2, 2/3, and 3/4

8. Which of the following is the LCD for 1/6 and 2/9?

a

18

b

36

c

9

d

54

9. If you want to add 1/4 and 3/10, what is the smallest common denominator you should use?

a

10

b

20

c

40

d

12

Use the LCD to rewrite the following fractions with a common denominator. Then, compare them using <, >, or =.

10. 2/3 and 5/6

11. 3/4 and 7/10

12. 1/5 and 2/7

13. Sarah ate 1/3 of a pizza, and Tom ate 2/5 of the same pizza. Who ate more pizza? Show your work using the LCD.