Question

1. find the LCD of 3/5 and 1/6.

A. 5
B. 6
C. 11
D. 30

2. what is the difference between 3/7 and 1/14.
A. 1\2
B. 4/14
C. 5/14
D. 9/14

3. if Sandy's cookie recipe calls for 1/3 cup of brown sugar and she increases it by 2/9 of a cup, how much brown sugar does she use?
A. 7/9 cup
B. 5/9 cup
C. 4/9 cup
D. 1/9 cup

4. what value could be added to 2/15 to make the sum greater than 1/2?
A. 1/15
B. 8/30
C. 5/15
D. 8/15

5. which set of mixed numbers has a difference less than 1?
A. 1 2/9, 1 1/9
B. 3 4/7, 2 1/7
C. 2 4/5, 1 1/3
D. 2 7/9, 1 1/3

Answer 1

1. LCD of 3/5 and 1/6 is 30

2. 3/7 - 1/14 = 6/14 - 1/14 = 5/14

3. 1/3 + 2/9 = 3/9 + 2/9 = 5/9

4. 8/15

5. 1 2/9 - 1 1/9

Answer 2

1. D. 30

2. C.
`(5)/(14)`

3.
`(5)/(9)`

4. D.
`(8)/(15)`

5. A.
`(12)/(9), (11)/(9)`

Explanation:

1. LCD or lowest common denominator for a set of fractions is lowest common multiple of all the denominators in that set of fractions

∴ for
`(3)/(5)` and
`(1)/(6)` LCD will be 5×6 = 30

2.
`(3)/(7) - (1)/(14)  = (6-1)/(14) = (5)/(14)`

3.
`(1)/(3) - (2)/(9)  = (3+2)/(9) = (5)/(9)` =
`(5)/(9)`

4.
`(2)/(15) + (1)/(15) = (1)/(5)\\\\(2)/(15) + (8)/(30) = (2)/(5)\\\\(2)/(15) + (5)/(15) = (7)/(15)\\\\(2)/(15) + (8)/(15) = (2)/(3)`

5.
`(12)/(9) - (11)/(9) = (1)/(9) \\\\(34)/(7) - (21)/(7) = (13)/(7) \\\\(24)/(5) - (11)/(3) = (17)/(15)\\\\(27)/(9) - (11)/(3) = (-6)/(9)`