Compound Units
Use compound units such as speed (distance ÷ time), unit pricing (cost ÷ quantity), and density (mass ÷ volume); solve problems involving compound units
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Teaching Table · Reviewed guide
Set out your lesson
“A compound unit combines two measurements, such as km/h, dollars per item, or grams per millilitre. Divide the first quantity by the second and keep both units.”
Bring to the table
- Paper
- Pencil
- Calculator if useful
Full guide and materials
- Paper
- Pencil
- Calculator if useful
- Step 1. Calculate 36 km ÷ 2 h = 18 km/h.
- Step 2. Compare $3/500 g = $0.006/g with $3.75/750 g = $0.005/g.
- Step 3. Calculate 120 g ÷ 60 mL = 2 g/mL.
- Step 4. Write what each quotient means and retain its units.
- Quick check. Success means calculating 45 km ÷ 3 h = 15 km/h, comparing $4/500 g with $5.40/900 g by unit price, and calculating 150 g ÷ 50 mL = 3 g/mL with correct units.
Worked example. 36 km in 2 h gives 18 km/h: 18 kilometres for each hour at that average rate.
Optional challenge. Create a metric compound-unit example and explain why the base units must match for a fair comparison.
What to notice. Photo of calculations with units or parent note recording speed, better unit price, density, and explanations.
Family records and proof options
Keep a record of your learning
Save photos, notes, and attendance. Export a proof packet for compliance or portfolio reviews.
Learning resources
Reviewed external links that reinforce this concept. They do not replace Gakuva’s teaching approach.
No reviewed resources for this concept yet.
The teaching approach above still stands. Curated practice links will appear here as the shelf fills.
Check understanding
- Calculate average speed given distance and time, converting between km/h and m/s if needed
- Compare unit prices of two products sold in different quantities to find the better deal
- Use the density formula to find mass, volume, or density given the other two values
“If a car travels 150 miles in 2.5 hours, can your child work out its average speed — and use the same idea to solve problems about price per kilogram or density of a material?”
Curriculum record
- Type
- Procedural
- Subject
- Mathematics
- Domain
- Ratio & Proportion
- Age range
- Ages 11–14
Standards