Unit 6: Operations with Fractions

Q1. 2/7 + 3/7 = ?

5/7 5/14 6/7 1

Solution: Same denominator, so just add the tops: 2+3=5, over 7

Q2. 5/9 u2212 2/9 = ?

7/9 3/9 3/18 2/3

Solution: Same denominator, subtract the tops: 5u22122=3, over 9, which reduces to 1/3

Q3. 1/2 + 1/5 = ?

6/10 2/7 7/10 3/10

Solution: Common denominator 10: 1/2=5/10, 1/5=2/10, and 5/10+2/10=7/10

Q4. 3/4 u00d7 2/5 = ?

6/9 5/9 1/2 6/20(3/10)

Solution: Multiply straight across: 3u00d72=6, 4u00d75=20, which reduces to 3/10

Q5. 5 u00d7 1/3 = ?

5/3 (1 2/3) 5 1/15 3/5

Solution: 5 u00d7 1/3 = 5/3, which is 1 2/3 as a mixed number

Q6. 2/3 u00f7 1/6 = ?

2 4 1/4 12

Solution: Solution: Keep, change, flip: 2/3 u00d7 6/1 = 12/3 = 4

Q7. 3 1/3 + 1 1/6 = ?

4 1/3 4 2/3 4 1/2 5

Solution: Convert 1/3 to 2/6: 3 2/6 + 1 1/6 = 4 3/6 = 4 1/2

Q8. 7/8 u2212 3/4 = ?

4/8 (1/2) 3/8 1/4 1/8

Solution: Convert 3/4 to 6/8: 7/8 u2212 6/8 = 1/8.

Q9. A recipe needs 2/3 cup of flour, and you want to double it. How much flour?

4/3 cups 2/6 cup 1/3 cup 4/6 cup

Solution: 2/3 u00d7 2 = 4/3, which is 1 1/3 cups.

Q10. 1/4 u00f7 1/2 = ?

2 1/2 1/8 1/4

Solution: Keep, change, flip: 1/4 u00d7 2/1 = 2/4 = 1/2

Q11. 4 1/2 u2212 2 1/4 = ?

2 1/2 1 3/4 2 1/4 2 3/4

Solution: Convert 1/2 to 2/4: 4 2/4 u2212 2 1/4 = 2 1/4

Q12. 2/5 u00d7 5/6 = ?

1/2 2/3 1/6 1/3

Solution: Multiply straight across: 2u00d75=10, 5u00d76=30, which reduces to 1/3

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