M3.7.2 For the adult
Bar charts and pie charts
Twelve of 36 children walk to school. How big is the walk sector of a pie chart?
What this chapter teaches
A bar chart compares classes and starts at zero. A pie chart shows parts of a whole: each angle is count ÷ total × 360°. The angle out of 360° is also the fraction of the whole.
Three questions to ask
There is no one right wording. Listen for the idea.
- How do you work out the angle for 5 children out of 30?
- Why is there a gap between the bars for counted data?
- What fraction of a pie chart is a sector of 90°?
After the chapter, the learner can
- Draw a bar chart for grouped data
- Draw a pie chart by working out the angles
- Read a pie chart to find fractions of the whole
What they copy into their notebook
A bar chart starts at 0, has equal steps and a gap between bars. A pie chart sector is count ÷ total × 360°. Sector angles add up to 360°. A sector of 90° is a quarter.