Mathematical Blogging 3

Topic: Multiplication and Division

Question L:

Wendy has 24 sweets. She shares them equally with her sister.
Wendy then eats 5 sweets from her share. How many sweets does Wendy have now?

Amy’s solution: 24 – 5 = 19
Wendy has 19 sweets left.
There is something wrong with Amy’s solution.

1. Explain the mistake in Amy’s solution.
2. Show how you would find the answer to the problem.

Question M:

In a class there are 17 girls and 18 boys.
Each pupil has 5 storybooks.
The teacher wants to know how many storybooks the children have altogether.

Ben’s solution: 17 x 5 = 85
85 + 18 = 103
The children have 103 storybooks altogether.

There is something wrong with Ben’s solution.
1. Explain the mistake in Ben’s solution.
2. Show how you would find the answer to the problem.

Question H:

Henry has 840 picture cards. He gave 70 cards to his brother.
The remaining cards are shared equally among 7 of his friends.
How many picture cards did each friend receive?

Tony’s solution: 840 ÷ 7 = 120
120 - 70 = 50
Each friend receives 50 picture cards.

There is something wrong with Tony’s solution.
1. Explain the mistake in Tony’s solution.
2. Show how you would find the answer to the problem.