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National Numeracy Challenge

Did you come across the pizza question Money Saving Expert Martin Lewis posed for National Numeracy Day?

What’s better value, one 15-inch diameter pizza for £10 or two 10-inch diameter pizzas for £10?

You work it out by finding the area of each pizza.

The area of a circle is 3.14 times the radius of the circle squared (ie, the radius multiplied by itself.)

So for the 15-inch pizza, that would be 3.14 x 7.5 x 75 = 176.625 square inches

For the two ten-inch pizzas, it would 2 x 3.14 x 5 x 5 = 157 square inches.

You can see Martin and Susanna discuss the sum with Dara O Briain on Good Morning Britain here https://www.youtube.com/watch?v=D3Z24LWsRmk

Dara uses the diameters of the pizzas to make a rough calculation that gives an answer to the question which is the better value. He shows how estimation gives you the information you need to make a decision. Susanna, though, makes the killer point that her children would prefer one pizza each: “We’re talking about maths analysis versus actual practicalities.” It’s difficult to argue with that.

Take the National Numeracy Challenge yourself at https://www.nationalnumeracy.org.uk/challenge/

Multiply is the Adult and Family Learning service’s project to support numeracy learning. Give your numeracy skills a boost! Contact us at multiply@moray.gov.uk or call 07929 785010

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