Lesson Notes By Weeks and Term v4 - JHS 3

Lesson Video

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Performance objectives

• Define ratios and proportions.
• Identify and create ratios from real-life situations.
• Solve problems involving proportions.
• Apply ratios and proportions to everyday scenarios in Ghana.

Lesson summary

This lesson introduces the concepts of Ratios and Proportion, which are powerful mathematical tools we use every single day, often without even realising it. From the kitchen where we cook to the market where we shop, and even on the football pitch, ratios and proportions help us to compare quantities and make fair and accurate calculations. Understanding this topic helps us to make better decisions in our daily lives, ensuring fairness, consistency, and proper planning. For instance, how does a caterer know the exact amount of rice and water to cook for 50 people if they only have a recipe for 5 people? This is the power of ratios and proportion.

Lesson notes

What is a Ratio?

A ratio is a way of comparing two or more quantities of the same kind and in the same unit. It tells us how much of one thing there is compared to another. Key Idea: Think of it as a "for every" relationship. For example, "for every 2 cups of rice, we need 4 cups of water." How to Write Ratios: We can write a ratio in three main ways: Using a colon ( : ), e.g., 2 : 4 Using the word "to", e.g., 2 to 4 As a fraction, e.g., 2/4 Simplifying Ratios: Just like fractions, ratios can be simplified by dividing all parts of the ratio by their highest common factor (HCF). A ratio of 2:4 can be simplified by dividing both numbers by 2, which gives us 1 : 2. This means the relationship is the same: for every 1 cup of rice, you need 2 cups of water.