Common Denominator
(5/7) + (6/7)
11/7 or 1 4/7
11 3/10 + 9 1/4
20 11/20
(2/5) + (1/2)
(9/10)
14 3/8 - 5 3/4
8 5/8
Mrs. Campbell made cookies. One recipe calls for 3 ΒΌ cups of flour. The second recipe calls for 2 1/5 cups flour. How much flour did she use in all?
"In all" is a clue to add! 5 9/20
(5/9) - (2/9)
(3/9) or (1/3)
4 5/8 - 2 3/8
2 2/8 or 2 1/4
(1/4) + (2/3)
(11/12)
8 1/3 - 1 5/6
6 3/6 or 6 1/2
Jordyn has a jumprope that is 6 1/3 feet long. Taylor's jumprope is 4 2/3 feet long. How much longer is Jordyn's rope?
Subtract! Clue phrase, "How much longer," so we know we are looking for a difference.
Answer: 1 2/3
(4/5) + (1/5)
(5/5) or 1
3 1/2 + 2 2/3
5 7/6 or 6 1/6
(5/6) - (7/10)
(4/30) or (2/15)
4 1/4 - 2 3/4
1 2/4 or 1 1/2
Before she went to the hairdresser, Sheila's hair was 7 1/2 inches long. When she left the salon, it was 5 1/4 inches long. How much of her hair did Sheila cut off?
Subtract. We are looking for the difference between the length of Sheila's hair before and after.
Answer: 2 1/4 inches
(9/10) - (9/10)
0
(13 7/10) + (4 1/6)
(17 26/30) or (17 13/15)
(9/10) - (2/3)
(7/30)
9 - 3 3/5
5 2/5
Ben and Daniel wanted to see who was taller. They had their mom measure their heights with a yardstick. Ben was 52 3/8 inches tall, and Daniel was 48 1/3 inches tall. How much taller is Ben than Daniel?
Subtract. "How much taller," indicates we are looking for a difference.
Answer: 4 1/24
(3/8) + (7/8)
(10/8) or (1 1/4)
3 3/8 + 6 5/8
10
(9/12) - (1/3)
(5/12)
7 - 5 1/2
1 1/2
Before she went to the hairdresser, Sheila's hair was 7 1/2 inches long. When she left the salon, it was 5 1/4 inches long. How much of her hair did Sheila cut off?
Subtract. You are looking for the difference in how long her hair was and how long it is now.
Answer: 2 1/4 inches.