Unit price detective

Grade 6 mathematics · 15 minutes · Rates

Compare unit prices and explain when the lower unit price is useful.

Classroom activity

Shop A sells 4 identical notebooks for $6. Shop B sells 6 for $8.40.

1. Find the price of one notebook in each pack. Show a calculation and label the unit.
2. Which shop has the lower unit price? What is the saving per notebook?
3. You need exactly 12 notebooks. Compare the total costs.
4. You only need 4 notebooks and have $7. Which pack can you buy? Explain why the lower unit price does not settle every purchasing decision.

Spend 4 minutes calculating, 4 comparing explanations, and 3 discussing the final question.

Check understanding

A 3 kg bag costs $7.20. A 5 kg bag costs $11.50. Which has the lower price per kilogram? Show both rates.

Teacher guide and answers

A costs $1.50 each; B costs $1.40, saving $0.10 each. Twelve cost $18 at A and $16.80 at B. With $7 and a need for 4, A is affordable while B is not. The check rates are $2.40/kg and $2.30/kg, so the 5 kg bag has the lower unit price. Ask learners to name what each quotient measures. Extend by comparing equal quantities using a common multiple.

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Grade 6 topic reference. Confirm your adopted standards; topic guidance does not certify alignment.