Mind MapMath · P5 / P6Ratio
Ratio One-Page Mind Map
See every part of ratio in one glance.
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Part to part
Compare one group with another. Order matters.
Part to whole
Add the parts to see the whole.
Total units
Total ÷ total units = 1 unit.
1
What is Ratio?
A ratio compares two or more quantities using units. Order matters: 2 : 3 is NOT the same as 3 : 2.
2
Part-to-Part
Compares one group to another.
- Boys : Girls = 2 : 3
- For every 2 boys there are 3 girls
3
Part-to-Whole
Compares one group to the total.
- Boys : Total = 2 : 5
- 2 out of every 5 people are boys
4
Total Units
Add all parts of the ratio to get total units. Then divide the total quantity by units to find 1 unit.
- Ratio 2 : 3 → Total = 5 units
- If total = 20, then 1 unit = 4
Common Mistakes
- Mixing up part-to-part with part-to-whole
- Forgetting to simplify the final ratio
- Not checking what each unit represents in the bar model
Teaching Team Tip
Always circle the question first. If it says 'what fraction of the total', you need part-to-whole — not part-to-part.
Worked Example
Try it, then check the steps
Question
The ratio of boys to girls in a class is 2 : 3. There are 20 students altogether. How many boys are there?
Steps
- 1Total units = 2 + 3 = 5 units
- 25 units = 20 students → 1 unit = 4 students
- 3Boys = 2 units = 2 × 4 = 8 boys
What to do next
Learn Ratio
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