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

Grade 10 › T3U09 Unit Pricing & Currency Exchange › L1
GRADE 10 · ALBERTAOUTCOME AB-MAT10-3-N1

L1 · Unit Pricing and the Best Buy

Learning goal

“I can find the unit price of an item two ways - with a unit rate and with equivalent fractions - and I can judge a best buy using cost AND quality, quantity and waste.”

Unit price — the cost for ONE standard amount of an item: $1.30 per litre, $0.36 per 100 g.
Unit rate — a rate whose second amount is 1: $5.20 for 4 L scaled down to $1.30 for 1 L.
Equivalent fractions — two fractions naming the same rate: $6.00/300 g = $2.00/100 g.
Best buy — the choice with the best value for your situation - lowest unit price, but also quality, how much you need, and what will be wasted.
Worked example

A 4 L jug of milk costs $5.20. Find the unit price per litre. Step 1: Unit price means the cost for 1 L. On the rate table, scale $5.20 : 4 L down by dividing both amounts by 4. Step 2: 5.20 / 4 = 1.30. The unit price is $1.30 per litre. Second method, same numbers - equivalent fractions: $5.20/4 L = $2.60/2 L = $1.30/1 L. Each step divides the price and the amount by the same number, so the rate never changes. On the double number line: litres 0, 1, 2, 4 align with dollars 0, 1.30, 2.60, 5.20 - the mark above 1 L IS the unit price. Say it plainly: two tools, one idea - shrink the rate until the second amount is 1.

Check yourself — explain it

Dividing both amounts by 4 keeps the rate the same because...

Paired problem — example still visible

500 g of pasta costs $1.80. Find the unit price per 100 g. -> 500 g holds five 100 g units; 1.80 / 5 = $0.36 per 100 g

Faded completion — last step is yours

"6 juice boxes cost $3.00, so 1 juice box costs 3.00 / ___ = $___" -> 6; 0.50

Ready to practise?

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

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