Addition and Subtraction of Dissimilar Fraction Word Problems

1. A chef adds 8/5 cup of vegetable broth and 3 cups of chicken broth. How much broth did he add in total?

Solution

8/5 + 3

Convert 3 to fifths

3 = 15/5

8/5 + 15/5 = 23/5

2. Lily used 3/2 meter of blue ribbon and 4/3 meter of red ribbon. What is the total length used?

Solution

LCD = 6

3/2 = 9/6

4/3 = 8/6

9/6 + 8/6 = 17/6

3. Maya used 2 liters of orange juice, 5/3 liter of pineapple juice, and 4 liters of cranberry juice. How much fruit punch was made?

Solution

2 + 4 = 6

6 = 18/3

18/3 + 5/3 = 23/3

4. A fishmonger had 3 1/2 crates of fresh fish. He sold 1 3/4 crates to a restaurant. How many crates of fish does the fishmonger have left?

Solution

3 1/2 − 1 3/4

Convert to fourths

3 1/2 = 3 2/4

3 2/4 − 1 3/4

Borrow 1 from 3

2 6/4 − 1 3/4

(2 − 1) = 1

6/4 − 3/4 = 3/4

Answer = 1 3/4

5. A baker started with 1 whole cake. He sold 1/4 of the cake in the morning and 2/5 of the cake in the afternoon. What fraction of the cake is left?

Solution

1/4 + 2/5

LCD = 20

1/4 = 5/20

2/5 = 8/20

5/20 + 8/20 = 13/20

1 − 13/20

20/20 − 13/20 = 7/20

6. A gardener had 5 bags of potting soil. He used 2 3/4 bags of soil for planting flowers. How many bags of potting soil does the gardener have left?

Solution

5 − 2 3/4

Convert to fourths

5 = 20/4

2 3/4 = 11/4

20/4 − 11/4 = 9/4

9/4 = 2 1/4

7. A provincial disaster response warehouse had 7 3/4 tons of relief rice in storage. During distribution, 2 1/2 tons were sent to one municipality and another 3 2/3 tons were delivered to a neighboring town. How many tons of rice remain in the warehouse?

Solution

7 3/4 − 2 1/2 − 3 2/3

Convert to improper fractions

7 3/4 = 31/4

2 1/2 = 5/2

3 2/3 = 11/3

LCD = 12

31/4 = 93/12

5/2 = 30/12

11/3 = 44/12

93/12 − 30/12 − 44/12

= 19/12

= 1 7/12