Increase or decrease by a percent — Speed Calculation
To raise a price by 15% you could find 15% and add it on — two steps. Faster: the new price is 100% + 15% = 115% of the old one, so multiply by 1.15 in one go. A fall of 15% leaves 85%, so multiply by 0.85.
Work it out in your head or on paper, then tap your answer — or type it and press Check. Stuck? Press “Show me how”.
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🏁 Lesson 23 test
20 questions. Check each answer, then go to the next one. Get 16 or more right to pass — and beat the clock: finish within 4 min.
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🖨️ Percentage Increase and Decrease Trick Worksheet
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