Percentages of Quantities Remember: A percentage is simply a fraction out of 100. 23% 56% 84% 0.23 0.56 0.84

Percentages of Quantities Remember: A percentage is simply a fraction out of 100. Calculating percentages using a calculator Example 1: Calculate 23% of £56 23 100 of 56 0.23 x 56 5 6 x 0. 2 3 = £12.88

Not to be taken down! 14% of 90 = 0.14 x 90 3% of 62 = 0.03 x 62 67% of 92 = 0.67 x 92

Percentages of Quantities Use your calculator to calculate the following. Q 1: Calculate 54% of £89 Q 2: Calculate 17% of 33 m £48.06 5.61 m Q 3: Calculate 84% of 350 g Q 4: Calculate 24% of $450 294 g $108 Q 5: Calculate 71% of 28 l Q 6: Calculate 43% of 16 kg 19.88 l 6.88 kg Q 7: Calculate 7% of £750 Q 8: Calculate 39% of 7.2 km £52.50 2.808 km

Example 1: Increase $60 by 32% Percentage increase using a calculator Example 1: Increase $60 by 32% We need to find 32% of 60, then add it to 60 60 + 0.32 x 60 = 60 x 1 + 0.32 x 60 Which combines to 60 x 1.32 6 x 1. 3 2 = $79.20

Not to be taken down! Increase 90 by 14% = 1.14 x 90 Increase 62 by 3% = 1.03 x 62 Increase 92 by 67% = 1.67 x 92

Percentage Increases Use your calculator to calculate the following. Q 1: Increase 80 by 3% Q 2: Increase 54 by 13% 82.4 61.02 Q 3: Increase 320 by 14% Q 4: Increase 640 by42% 364.8 908.8 Q 5: Increase 94 by 11% Q 6: Increase 48 by 16% 104.34 55.68

Example 1: Decrease $60 by 32% Percentage decrease using a calculator Example 1: Decrease $60 by 32% We need to find 32% of 60, then take it away from 60 60 - 0.32 x 60 = 60 x 1 - 0.32 x 60 1 – 0.32 = 0.68 Which combines to 60 x 0.68 6 x 0. 6 8 = 40.8

Not to be taken down! Decrease 90 by 14% = 0.86 x 90 Decrease 62 by 3% = 0.97 x 62 Decrease 92 by 67% = 0.33 x 92

Percentage Decreases Use your calculator to calculate the following. Q 1: Decrease 80 by 3% Q 2: Decrease 54 by 13% 77.6 46.98 Q 3: Decrease 320 by 14% Q 4: Decrease 640 by42% 275.2 371.2 Q 5: Decrease 94 by 11% Q 6: Decrease 48 by 16% 83.66 40.32

Repeated Percentage Change $40 000 is invested at 5% per annum for 10 years. How much will the investment be worth after 10 years? This will allow you to do the power of 10 We need to multiply 40 000 by 1.05 ten times! 40 000 x 1.0510 = $65155.79

$60 000 is invested at 12% per annum for 5 years $60 000 is invested at 12% per annum for 5 years. How much will the investment be worth after 5 years? $105740.50 A car worth $24 000 depreciates at 15% per annum for 6 years. How much will the car be worth after 6 years? $9051.59