L4 · Pricing Clinic

Learning goal

“I can walk into any pricing situation in this unit - unit price, best buy, percent change, promotions, currency - pick the right tool without being told which one it is, and defend my answer.”

Unit price — cost for one standard amount (from L1).

Percent change — change / original x 100 (from L2).

Selling / purchasing rate — the office sells foreign money at the selling rate; it buys it back at the purchasing rate (from L3).

Worked example

Worked example 1. A 750 g box of cereal costs $4.50. A flyer for another store says "cereal - only $0.70 per 100 g!" Which store is cheaper? Step 1: Name the tool: the amounts differ, so compare unit prices. Step 2: Box: 4.50 / 7.5 = $0.60 per 100 g. Flyer: $0.70 per 100 g. Step 3: The boxed cereal is cheaper - the flyer's "only" is doing persuasion, not math. Worked example 2. A US website lists headphones at 45 USD. The selling rate is 1 USD = 1.38 CAD. Estimate the Canadian cost. Step 1: Name the tool: currency conversion, estimate first. Step 2: 45 x 1.38 = $62.10, so about $62 CAD (plus any shipping - the estimate tells you the neighbourhood, not the final bill).

Check yourself — explain it

The first move in a mixed problem is...

Paired problem — example still visible

A 2 L bottle of pop costs $2.50; a 500 mL can costs $0.85. Which is the better buy per litre? -> 2 L: $1.25 per L. Can: 0.85 x 2 = $1.70 per L -> the 2 L bottle

Faded completion — last step is yours

"$56 drops to $42: change = $14; percent decrease = 14 / ___ x 100 = ___%" -> 56; 25

Ready to practise?

10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.

Start practice →Take the unit quiz

Grade 10 — Mathematics 10-3 › T3U09 Unit Pricing & Currency Exchange

L4 · Pricing Clinic