Imagine a village competition — who can collect the most waste and keep the streets cleanest? In this chapter, we use maths to track the waste collected each day, compare amounts, and solve problems set in real-life situations. We also learn to read and interpret simple tables and bar graphs.
Reading a Table
A table organises information in rows and columns for easy comparison.
Example table — Waste collected (in kg):
| Day | Village A | Village B |
|---|---|---|
| Monday | 25 | 32 |
| Tuesday | 30 | 28 |
| Wednesday | 40 | 35 |
From the table: Village B collected more on Monday; Village A collected more on Tuesday and Wednesday.
Reading a Bar Graph
- A bar graph uses bars (rectangles) to show amounts. The taller the bar, the larger the value.
- The horizontal axis (x-axis) shows categories (e.g., days).
- The vertical axis (y-axis) shows the values (e.g., kg of waste).
- Always check the scale — e.g., each small mark may equal 5 kg.
Addition and Subtraction in Context
We use addition to find totals and subtraction to find differences.
In the table above, what is the total waste collected by Village A over 3 days?
25 + 30 + 40 = 95 kg.
On Wednesday, by how many kg did Village A beat Village B?
40 - 35 = 5 kg.
A bar on a graph reads 45 on the y-axis. Another bar reads 60. What is their combined total?
45 + 60 = 105 kg.
Over Monday and Tuesday, Village B collected 32 + 28 = 60 kg. Village A collected 25 + 30 = 55 kg. Which village collected more and by how much?
Village B collected more by 60 - 55 = 5 kg.
If each family donated 3 hours of cleaning over 5 days, how many hours total?
3 x 5 = 15 hours per family.
Key Skills
- Read values from a table or bar graph carefully.
- Find total using addition.
- Find difference using subtraction.
- Compare two quantities using > (greater than) or < (less than).
Common mistakes
- Misreading the scale of a bar graph (e.g., each marking could be 2 or 5, not always 1).
- Forgetting to include all rows when finding a total.
Summary
Tables and bar graphs display information clearly. Use addition to find totals and subtraction to find differences. Always read the scale of a graph before interpreting values.