Lesson Notes By Weeks and Term - Primary 6

Ratio: population issues

Week 7

Subject: Mathematics

Topic: Ratio: population issues

Reference: Macmillian champion primary mathematics book 6

Previous knowledge: Pupils are familiar with Ratio and proportion.

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

  1. Find amount of money of money allocated for health care of individual citizen in a year.
  2. Express number of children per family in ratio form.


Population and Facilities

Government allocates money in their budgets to provide facilities for the population. In Nigeria, we have three types of government. They are:

  1. Local government area
  2. State
  3. Federal government

Example 1: a local government area (LGA) has a population of 87 000 people. A sum of N26 100 00 is to be spent on health care in a year. Calculate the amount of number allocated for each citizen.


Ratio of people to the money allocated is = 87 000: 261 000 00

                        = 87: 26 100 (divide by 1000)

                        = 29: N8 700 (divide by 3)

                        = 1: N300 (divide by 29)

The amount of money allocated on health care for each citizen is N300.

Lesson 2: ratio of children to family

Example 1: the total number of children in a community of 24 families is 96. Calculate the ratio of children per family.


Ratio of children per family = 24 families: 96 children

                    Divide both by 24


There are 4 children per family

Lesson 3: ratio of birth to death

Birth rate is expressed as the number of birth per 1000 in a population. Fertility rate is the number of children born per woman in a population. Death rate (morality rate) is expressed as the number of death per 1000 in a population.

Example 1: if 5076 children were born in a year in a city with population 141 000, calculate the birth rate.


Ratio of population to number of birth            36

    141 000:5076

    Divide both by 141






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


  1. A total of 5966 children were born in a year in a city with population 157 000. Calculate the birth rate.

Ratio of population to number of birth

157 000:5 966

Divide both side by 157


That is, the birth rate is 38 birth /1000

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

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