This resource provides animated demonstrations of the mathematical method Check animations and delete slides not needed for your class 80 80 80 Using decimals to find a percentage of a quantity ID: 1028078
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1. Calculating a Percentage Multiplier – DemonstrationThis resource provides animated demonstrations of the mathematical method.Check animations and delete slides not needed for your class.
2. 808080Using decimals to find a percentage of a quantity.300% = 80 × 38080200% = 80 × 280100% = 80 × 150% = 80 × 0.540
3. 90Using decimals to find a percentage of a quantity.100% = 90 × 150% = 90 × 0.575% = 90 × 0.7527% = 90 × 0.274567.524.3
4. 70Use a decimal to calculate these percentages of quantities.100% = 70 × 150% = 70 × 0.5270100% = 270 × 175% = 270 × 0.7520% = 70 × 0.232% = 270 × 0.3290% = 70 × 0.967% = 270 × 0.6735% of 70 = 12.5% of 270 = 451463202.586.4180.924.533.75
5. Increasing & Decreasing using a Decimal Multiplier100%120%0.290 × (1 + 0.2)1.2Increase 90 by 20%= 90 × 1.2= 108100%130%0.390 × (1 − 0.3)0.7Decrease 90 by 30%= 90 × 0.7= 63
6. Increasing & Decreasing using a Decimal Multiplier100%145%0.45140 × (1 + 0.45)1.45Increase 140 by 45%= 140 × 1.45= 203100%115%0.15140 × (1 − 0.15)0.85Decrease 140 by 15%= 140 × 0.85= 119
7. Increasing & Decreasing using a Decimal Multipliera) Increase 180 by 40%252b) Increase 230 by 35%310.5c) Increase 110 by 27%139.7d) Decrease 240 by 30%168e) Decrease 510 by 45%280.5f) Decrease 330 by 19%267.3
8. Increase 250 by 20%100% = 1.0020% = 0.20++120% = 1.20250 × 1.20 = Using a percentage multiplier300
9. Increase 250 by 20%100% = 1.0020% = 0.20++120% = 1.20250 × 1.20 = Using a percentage multiplier300Increase 320 by 40%100% = 1.0040% = 0.40++140% = 1.40320 × 1.40 = 448Your Turn
10. Increase 280 by 15%100% = 1.0015% = 0.15++115% = 1.15280 × 1.15 = Using a percentage multiplier322
11. Increase 280 by 15%100% = 1.0015% = 0.15++115% = 1.15280 × 1.15 = Using a percentage multiplier322Increase 340 by 35%100% = 1.0035% = 0.35++135% = 1.35340 × 1.35 = 459Your Turn
12. Increase 310 by 22%100% = 1.0022% = 0.22++122% = 1.22310 × 1.22 = Using a percentage multiplier378.2
13. Increase 310 by 22%100% = 1.0022% = 0.22++122% = 1.22310 × 1.22 = Using a percentage multiplier378.2Increase 260 by 17%100% = 1.0017% = 0.17++117% = 1.17260 × 1.17 = 304.2Your Turn
14. Increase 230 by 16.5%100% = 1.015.5% = 0.165++116.5% = 1.165230 × 1.165 = Using a percentage multiplier267.95
15. Increase 230 by 16.5%100% = 1.015.5% = 0.165++116.5% = 1.165230 × 1.165 = Using a percentage multiplier267.95Increase 170 by 21.5%100% = 1.021.5% = 0.215++121.5% = 1.215170 × 1.215 = 206.55Your Turn
16. Increase 150 by 6.3%100% = 1.006.3% = 0.063++106.3% = 1.063150 × 1.063 = Using a percentage multiplier159.45
17. Increase 150 by 6.3%100% = 1.006.3% = 0.063++106.3% = 1.063150 × 1.063 = Using a percentage multiplier159.45Increase 230 by 3.7%100% = 1.003.7% = 0.037++103.7% = 1.037230 × 1.037 = 238.51Your Turn
18. Increase 310 by 22%100% = 1.0022% = 0.22++122% = 1.22310 × 1.22 = Using a percentage multiplier378.2A) Increase 340 by 20%Your TurnB) Increase 250 by 60%C) Increase 410 by 15%D) Increase 330 by 45%E) Increase £5.40 by 32%F) Increase 823 g by 7%G) Increase 78 cm by 12.5%H) Increase 763 ml by 3.5%
19. Increase 310 by 22%100% = 1.0022% = 0.22++122% = 1.22310 × 1.22 = Using a percentage multiplier378.2A) Increase 340 by 20%Your TurnB) Increase 250 by 60%C) Increase 410 by 15%D) Increase 330 by 45%E) Increase £5.40 by 32%F) Increase 823 g by 7%G) Increase 78 cm by 12.5%H) Increase 763 ml by 3.5%408400471.5478.5£7.13880.61 g87.75 cm789.705 ml
20. Decrease 240 by 30%100% = 1.0030% = 0.370% = 0.7240 × 0.7 = Using a percentage multiplier168−−
21. Decrease 240 by 30%100% = 1.0030% = 0.370% = 0.7240 × 0.7 = Using a percentage multiplier168−−Decrease 180 by 40%100% = 1.0040% = 0.460% = 0.6180 × 0.6 = 108−−Your Turn
22. Decrease 130 by 15%100% = 1.0015% = 0.1585% = 0.85130 × 0.85 = Using a percentage multiplier110.5−−
23. Decrease 130 by 15%100% = 1.0015% = 0.1585% = 0.85130 × 0.85 = Using a percentage multiplier110.5−−Decrease 190 by 35%100% = 1.0035% = 0.3565% = 0.65190 × 0.65 = 123.5−−Your Turn
24. Decrease 270 by 17.5%100% = 1.0017.5% = 0.17582.5% = 0.825270 × 0.825 = Using a percentage multiplier222.75−−
25. Decrease 270 by 17.5%100% = 1.0017.5% = 0.17582.5% = 0.825270 × 0.825 = Using a percentage multiplier222.75−−Decrease 320 by 16.5%100% = 1.0016.5% = 0.16583.5% = 0.835320 × 0.835 = 267.2−−Your Turn
26. Decrease 140 by 7.5%100% = 1.007.5% = 0.07592.5% = 0.925140 × 0.925 = Using a percentage multiplier129.5−−
27. Decrease 140 by 7.5%100% = 1.007.5% = 0.07592.5% = 0.925140 × 0.925 = Using a percentage multiplier129.5−−Decrease 220 by 3.5%100% = 1.003.5% = 0.03596.5% = 0.965220 × 0.965 = 212.3−−Your Turn
28. Decrease 130 by 15%100% = 1.0015% = 0.1585% = 0.85130 × 0.85 = Using a percentage multiplier110.5−−A) Decrease 280 by 30%Your TurnB) Decrease 360 by 70%C) Decrease 430 by 25%D) Decrease 270 by 15%E) Decrease £4.40 by 27%F) Decrease 671 g by 6%G) Decrease 48 cm by 11.5%H) Decrease 621 ml by 2.5%
29. Decrease 130 by 15%100% = 1.0015% = 0.1585% = 0.85130 × 0.85 = Using a percentage multiplier110.5−−A) Decrease 280 by 30%Your TurnB) Decrease 360 by 70%C) Decrease 430 by 25%D) Decrease 270 by 15%E) Decrease £4.40 by 27%F) Decrease 671 g by 6%G) Decrease 48 cm by 11.5%H) Decrease 621 ml by 2.5%196108322.5229.5£3.21630.74 g42.48 cm605.475 ml
30. I’ve got an idea that’ll make millions!What happens when someone invests in a business?People can make more money by giving money to businesses.They hope the business uses the money to grow & increase their income.If the business does get bigger they will give the money back, plus interest.Hmmmm….But! What if the business is not successful?The investors can lose their money! +1%+8%+120%!−3%− 14%− 100%!
31. Banks make safe investments & give their customers a small interest rate.2% per annumin one yearYou can invest in many companies on the stock market.This can be much riskier!15% loss!
32. Is Sally correct?I invested $300 and got 120% back!Wow! $60!Original+100%+20%
33. Is this possible?I invested $500 and lost 200%!We can’t eat 200% of something & things in a shop can’t cost 200% less.A 100% decrease means everything is gone!But, if we can use negative numbers, we can lose over 100%.A company can make negative profit – they are spending money to just keep going!
34. Invested1 Year Interest$ @ End of Year$50050%$750$40025%$500$55020%$660$30015%$345$48035%$648$60041%$846$26085%$481$6000.5%$603$14002.5%$1435$1201.25%$121.50$8097.75%$158.20
35. InvestedLoss!$ @ End of Year$60050%$300$80025%$600$25020%$200$50015%$425$16035%$104$40041%$236$58085%$87$8000.5%$796$12002.5%$1170$1601.25%$158$5097.75%$1.13 (1.125)
36. InvestedProfit / Loss!$ @ End of Year$600+50%$900$800+25%$1000$250+20%$300$500+15%$575$300+41%$423$460+36%$625.60$260−10%$234$600−25%$450$1400−60%$560$120−75%$30$140−82%$25.20$120−97. 5%$3
37. Questions?Comments?Suggestions?…or have you found a mistake!?Any feedback would be appreciated .Please feel free to email:tom@goteachmaths.co.uk