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Many consumers thought that because 4 is bigger than 3, then 1 4 must be bigger than 1 3 ! A&W overestimated the public’s ability to understand the maths. As a result, their message was misunderstood and the burger failed.

Epic Fail 2: Is dishwashing powder really worth more per kilogram than silver?

Silver is worth about $1000 per kg. So, do you think this unit price in $ per kg of $7386.55 per kg for dishwashing liquid is correct?

Opportunities for class discussion.

Discussion questions

1 The unit price should have been $8.79 ÷ 1.19 = $7.38(655) per kg! Out by a factor of 1000 (three decimal places).

2 What do you think they did wrong?

Check mathematical information and numbers you see in the real world – don’t assume that the answer you get to your calculations is correct.

Check that your answers make sense. Use your maths knowledge and your other knowledge and experiences!

Develop a ‘feeling’ for numbers and quantities: that 1 3 is bigger than 1 4 and that dishwashing liquid is not worth more per kilogram than silver!