# Lesson Notes By Weeks and Term - Primary 6

Problems on percentage

Week 9

Subject: Mathematics

Topic: Problems on percentage

Reference: Macmillian champion primary mathematics book 6

Previous knowledge: Pupils are familiar with population issues.

Objective: At the end of the lesson pupils should be able to:

1. Express quantities as percentage.
2. Express a number as a percentage of another.
3. Work our percentage increase or decrease.

Content

Lesson 1: Expressing quantities as percentages

Example 1: there are 40 pupils in a class. If 25% are absent, how many pupils are present?

Solution

There are 40 pupils in the class

Pupils absent = 25% of 40

25100 X 40=10

Pupils present = 40-10 = 30

Example 2: there are 560 children in a school. One day 28 were absent. What percentage of children were at school on that day?

Solution

First method: children present = 560-28 = 532

Percentage of children present = children presentTotal number of childern X 1001%

= 532560 X 100%

= 95%

2nd method: % of children absent = 28560 X 100%=5%

Percentage of children present = 100% - 5% = 95%

Lesson 2: Expressing a number as a percentage of another

Example: Share N5 000 in the ratio N2 000 to N3000 among Jimoh and chinedu. What percentage of the money does each boy receives?

Solution

Total amount of money shared = N2 000 + N3 000 = N5 000

Jimoh’s share = N2 000

The percentage of the money he receives = Jimoh's shareTotal amount X 100%

= N 2 000N 5 000 X100%

= 40%

Chinedu’s share = N3 000

The percentage of the money he receives = Chinedu's shareTotal amount X 100%

= N3 000N5 000 X 100%

= 60%

Lesson 3: Expressing a number as percentage as another (cont’d)

Example: a pupil got 120 out of 200 marks in a test. Change this mark to a percentage.

Solution

Percentage mark of    120200= 120200 X 100%

= 60 %

Example 2: the market price of a chair is N6 000. Its sale price is N4 500. Find the reduction as a percentage of the market price.

Solution

Reduction = N6 000 – N4 500 = N1 500

ReductionMarket price %= N1 500N6 000 X 100%

= 14 X 100=25%

Presentation:

Step I: Teacher revises previous lesson with pupils

Step II: Teacher introduces and explain new topic to pupils

Step III: Pupils are allowed to ask questions

Step IV: Teacher writes note on the boards for pupils

Evaluation:

1. If 40% of the pupils in a school are boys, what percentage of the pupils are girls?
2. Express 712 % as a decimal.
3. There are 48 pupils in a class. If 75% were present, how many pupils were absent?
4. Change a mark of 180 out of 300 to a percentage.

Conclusion: Teacher moves round for inspection, marking and correction of notes where necessary.