Reverse Percentage Change – Non-Calculator – Demonstration This resource provides animated demonstrations of the mathematical method. Check animations and delete slides not needed for your class.

How many crisps were there in a packet before the increase? 50% EXTRA FREE! Now 300g! How many crisps were there in a packet before the increase? 100% = 200g 100% 50% 50% 100g 50% 100g 50% 100g 300g

How many sweets did you get 50% EXTRA FREE! Now 240 sweets! How many sweets did you get before the increase? 100% = 160 sweets 100% 50% 50% 80 50% 80 50% 80 240

How big was the burger before the increase? 100% = 120g 100% 25% 25% 25% BIGGER! Now 150g! How big was the burger before the increase? 100% = 120g 100% 25% 25% 30 25% 30 25% 30 25% 30 25% 30 150

How big was the drink before the increase? 100% = 240ml 100% 25% 25% 25% BIGGER! Now 300ml! How big was the drink before the increase? 100% = 240ml 100% 25% 25% 60 25% 60 25% 60 25% 60 25% 60 300

How big was the juice carton 20% EXTRA FREE! Now 240ml! How big was the juice carton before the increase? 100% = 200ml 100% 20% 20% 40 240

a packet before the increase? 20% EXTRA FREE! Now 42 in a packet! How many sweets were in a packet before the increase? 100% = 35 sweets 100% 20% 20% 7 42

How big was a bar of chocolate 10% EXTRA FREE! Now 66g! How big was a bar of chocolate before the increase? 100% = 60g 100% 10% 10% 6 66

How big was the cupcake before the increase? 100% = 80g 100% 10% 88 10% BIGGER! Now 88g! How big was the cupcake before the increase? 100% = 80g 100% 10% 10% 8 88

How big was the chocolate bar 5% BIGGER! Now 84g! How big was the chocolate bar before the increase? 100% = 80g 100% 5% 4 84 84 ÷ 21 = 4g

How big was the lollipop 5% BIGGER! Now 126g! How big was the lollipop before the increase? 100% = 120g 100% 5% 6 126 126 ÷ 21 = 6g

How big was a portion of fries 15% BIGGER! Now 69g! How big was a portion of fries before the increase? 100% = 60g 100% 15% 3 69 69 ÷ 23 = 3g

How big was the chocolate bar 15% BIGGER! Now 138g! How big was the chocolate bar before the increase? 100% = 120g 100% 15% 6 138 138 ÷ 23 = 3g

2) Find the original size of these items before the increase. 100% 50% 50% BIGGER! Now 90g! 1) How big was the burger before the increase? Was: 60g 90 2) Find the original size of these items before the increase. a) 50% BIGGER! Now 120g! b) 25% EXTRA! Now 75g! c) 20% MORE! Now 96ml! Was: 80g Was: 60g Was: 80ml 20% EXTRA! Now 60ml! d) e) 10% MORE! Now 132g! f) 15% BIGGER! Now 184g! Was: 50ml Was: 120g Was: 160g

2) Find the original size of these items before the increase. 100% 50% 50% BIGGER! Now 90g! 1) How big was the burger before the increase? Was: 60g 90 Answers 2) Find the original size of these items before the increase. a) 50% BIGGER! Now 120g! b) 25% EXTRA! Now 75g! c) 20% MORE! Now 96ml! Was: 80g Was: 60g Was: 80ml 20% EXTRA! Now 60ml! d) e) 10% MORE! Now 132g! f) 15% BIGGER! Now 184g! Was: 50ml Was: 120g Was: 160g

2) Find the original size of these items before the increase. 100% 50% 50% BIGGER! Now 75g! 1) How big was the burger before the increase? Was: 50g 75 2) Find the original size of these items before the increase. a) 50% BIGGER! Now 135g! b) 25% EXTRA! Now 150g! c) 20% MORE! Now 336m! Was: 90g Was: 120g Was: 280ml 20% EXTRA! Now 54ml! d) e) 30% MORE! Now 156g! f) 35% BIGGER! Now 243g! Was: 45ml Was: 156g Was: 180g

2) Find the original size of these items before the increase. 100% 50% 50% BIGGER! Now 75g! 1) How big was the burger before the increase? Was: 50g 75 Answers 2) Find the original size of these items before the increase. a) 50% BIGGER! Now 135g! b) 25% EXTRA! Now 150g! c) 20% MORE! Now 336m! Was: 90g Was: 120g Was: 280ml 20% EXTRA! Now 54ml! d) e) 30% MORE! Now 156g! f) 35% BIGGER! Now 243g! Was: 45ml Was: 120g Was: 180g

How much did the t-shirt cost SALE! 50% OFF! Now £15! How much did the t-shirt cost before the discount? How much do you save? 50% 50% 50% 15 15 £15 100% = £30

How much did the t-shirt cost SALE! 50% OFF! Now £6! How much did the t-shirt cost before the discount? How much do you save? 50% 50% 50% 6 6 £6 100% = £12

How much did the shoes cost SALE! 25% OFF! Now £60! How much did the shoes cost before the discount? How much do you save? 75% 25% 25% 20 20 £60 100% = £80

How much did the hoodie cost SALE! 25% OFF! Now £21! How much did the hoodie cost before the discount? How much do you save? 75% 25% 25% 7 7 £21 100% = £28

How much did the jeans cost SALE! 20% OFF! Now £28! How much did the jeans cost before the discount? How much do you save? 80% 20% 20% 7 7 £28 100% = £35

How much did the hoodie cost SALE! 20% OFF! Now £20! How much did the hoodie cost before the discount? How much do you save? 80% 20% 20% 5 5 £20 100% = £25

How much did the skirt cost SALE! 10% OFF! Now £54! How much did the skirt cost before the discount? How much do you save? 10% 90% 10% 6 6 £54 100% = £60

How much did the shoes cost SALE! 10% OFF! Now £63! How much did the shoes cost before the discount? How much do you save? 10% 90% 10% 7 7 £63 100% = £70

2) Find the price of the clothes before the sale. 75% 25% 1) How much was the cap before the discount? 25% OFF! Now £30! Was: £40 25% 2) Find the price of the clothes before the sale. a) b) c) 25% OFF! Now £27! 20% OFF! Now £40! 20% OFF! Now £28! Was: £36 Were: £50 Was: £35 10% OFF! Now £54! d) e) 30% OFF! Now £21! f) 35% OFF! Now £52! Were: £60 Was: £30 Was: £80

2) Find the price of the clothes before the sale. 75% 25% 1) How much was the cap before the discount? 25% OFF! Now £30! Was: £40 25% Answers 2) Find the price of the clothes before the sale. a) b) c) 25% OFF! Now £27! 20% OFF! Now £40! 20% OFF! Now £28! Was: £36 Were: £50 Was: £35 10% OFF! Now £54! d) e) 30% OFF! Now £21! f) 35% OFF! Now £52! Were: £60 Was: £30 Was: £80

1) How much were the socks before the discount? 75% 25% 1) How much were the socks before the discount? 25% OFF! Now £6! Were: £8 £6 2) Find the price of the clothes before the sale. a) b) c) 25% OFF! Now £24! 20% OFF! Now £36! 20% OFF! Now £52! Was: £32 Was: £45 Was: £65 10% OFF! Now £13.50! d) e) 60% OFF! Now £48! f) 45% OFF! Now £27.50! Was: £15 Were: £120 Was: £50

Answers 75% 25% 1) How much were the socks before the discount? 25% OFF! Now £6! Were: £8 £6 Answers 2) Find the price of the clothes before the sale. a) b) c) 25% OFF! Now £24! 20% OFF! Now £36! 20% OFF! Now £52! Was: £32 Was: £45 Was: £65 10% OFF! Now £13.50! d) e) 60% OFF! Now £48! f) 45% OFF! Now £27.50! Was: £15 Were: £120 Was: £50

tom@goteachmaths.co.uk Questions? Comments? Suggestions? …or have you found a mistake!? Any feedback would be appreciated . Please feel free to email: tom@goteachmaths.co.uk