Mathematics · Grades 6–9
Ratios, proportions and misleading comparisons · Revision card
A part-to-part ratio is not the same as a part-to-whole fraction.
Understand the idea
Identify the quantities
A part-to-part ratio is not the same as a part-to-whole fraction.
Use units
A rate compares quantities with stated units; cancel units only when appropriate.
Keep the baseline
Percentage change uses the original value as the reference.
Worked examples
A bag has 2 green beads for every 3 yellow beads. What fraction of all beads is green?
The total ratio is 2 + 3 = 5 parts.
2/5
A model uses 4 cm for 12 m. How many metres correspond to 7 cm?
12/4 = 3 m per cm; 7 × 3 = 21.
21
Explain without looking
- Which unit is suitable for an average speed?
Preview material · independent educational review required. Grade bands are approximate, not official curriculum alignment.