2
Fraction story problems
Discover Mathematics P2: Term 2, Lessons 101–110
GoalSolve story problems about a fraction of a group and about what is left.
New words
story problem · a short story that ends with a questionleft · what remains after some are takenequal groups · groups of the same size
Explanation
To solve a fraction story, first find the whole group. The bottom number tells how many equal groups to make. Find the size of one group. Then read the question: does it ask about the part, or about what is left? Youssef has 12 dates and eats half. Split 12 into 2 equal groups of 6. He eats 6. Then 12 − 6 = 6 dates are left.
Worked examples
A bag has 9 oranges. 1/3 of them are for juice. Split 9 into 3 equal groups of 3, so 3 oranges are for juice. 9 − 3 = 6 oranges are not for juice.
A box has 8 pencils. 1/4 of them are red. Split 8 into 4 equal groups of 2, so 2 pencils are red. 8 − 2 = 6 pencils are not red.
Nour reads 1/2 of a book with 16 pages. Split 16 into 2 equal groups of 8. She reads 8 pages and 8 pages are left.
Class activity
Act it out. Take 12 buttons or beans. Read a story aloud: “Karim has 12 beans. He gives 1/4 of them away.” Make 4 equal groups with the beans. Give one group away. How many did he give? How many are left? Make up two more stories with 1/2 and 1/3.
Practice
1
There are 10 apples. 1/2 of them are green. How many apples are green?
1/2 of 10 = 5 green apples.
2
12 balloons: 1/4 of them are blue. How many are blue? How many are not blue?
1/4 of 12 = 3 blue. 12 − 3 = 9 are not blue.
3
Farida has 9 stickers and gives 1/3 to Malak. How many stickers does Farida keep?
1/3 of 9 = 3 given. 9 − 3 = 6 stickers kept.
4
Marwan cuts a pizza into 4 equal slices. He eats 1 slice and his brother eats 2 slices. What fraction of the pizza is left?
4 − 1 − 2 = 1 slice is left, so 1/4 is left.
5
Omar has 6 cars. He puts 1/2 of them on a shelf. How many cars are not on the shelf?
1/2 of 6 = 3 on the shelf. 6 − 3 = 3 are not.