Number: Ratios and Proportion · JHS2 Mathematics

Lesson notes

Learning Objectives

Indicator: B8.1.4.1.1 - Use ratio reasoning to convert measurement units; manipulate and transform units appropriately when multiplying or dividing quantities.

By the end of the lesson, learners can:

Write conversion factors as ratios equal to 1 and use them to convert between metric units of length (cm, m, km), mass (g, kg), and capacity (ml, l).
Convert measurements from one unit to another using ratio reasoning, showing each step of the multiplication or division.
Determine the appropriate operation (multiply or divide) when converting between larger and smaller units, with justification.
Manipulate units correctly when multiplying or dividing quantities in compound situations, such as speed problems.
Compare speeds expressed in different units by converting to common units, and justify which is greater.

Sign in with your phone number to read the full note and download the GES plan - free.

Sign in with phone number

Curriculum details

Strand: Number (Strand 1)
Sub-strand: Number: Ratios and Proportion (1.4)
Content standard: B8.1.4.1 - Demonstrate an understanding of ratio, rate and proportions and use it these to solve real-world mathematical problems. Notes: put a passage for the graph
Indicator: B8.1.4.1.1 - Use ratio reasoning to convert measurement units; manipulate and transform units appropriately when multiplying or dividing quantities.
Suggested placement: Term 2, Week 2 (Week 14 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: Mathematics, Common Core Programme (JHS1-JHS3), 2023, p. 105
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

E.g.1 Convert (cm to m; km to m; ml to cm; etc.) one unit of measure to another using ratio reasoning.
• 1m = 100cm is a conversion factor, and we can write from it the ratios 1 m and 100 cm , with each being equivalent to 1. Then, to 100 cm 1 m
convert a measurement in metres into centimetres, we can multiply it by the ratio 1m/100cm.
E.g.2 Manipulate and use units appropriately to solve problems.
• Agbo walks 4km to school every day. He uses 60minutes. Rukiya uses 45minutes to cover 4200m. Which of the two learners is faster?