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

Grade 10 › T3U09 Unit Pricing & Currency Exchange › L2
GRADE 10 · ALBERTAOUTCOME AB-MAT10-3-N1

L2 · Percent Increase and Decrease in Pricing

Learning goal

“I can find the percent increase or decrease between an original price and a new price, apply a percent markup or discount to get a new price, and compare two promotions fairly.”

Percent increase — how much a price grew, expressed as a percent OF THE ORIGINAL price.
Percent decrease — how much a price fell, expressed as a percent OF THE ORIGINAL price.
Markup — the percent a store adds to its cost to set the selling price.
Discount — a percent taken off the price; a 25% discount means you pay 75%.
Worked example

A jacket's price rises from $40 to $50. What is the percent increase? Step 1: Find the change: 50 - 40 = $10. Step 2: Compare the change to the ORIGINAL price: 10/40 = 0.25. Step 3: As a percent: 0.25 x 100 = 25%. The percent increase is 25%. On the percent bar: the original $40 is the whole bar (100%). The extra $10 is one quarter of that bar - 25%. Say it plainly: percent change is always "change / ORIGINAL". The original is the whole; the new price is never the whole for this calculation.

Check yourself — explain it

The $10 increase is divided by $40 and not by $50 because...

Paired problem — example still visible

A skateboard drops from $80 to $60. Find the percent decrease. -> Change 20; 20/80 = 0.25 -> 25% decrease

Faded completion — last step is yours

"A price rises from $200 to $230: change = $30; percent increase = 30 / ___ x 100 = ___%" -> 200; 15

Ready to practise?

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

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