Tapping into mathematics
Tapping into mathematics

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Tapping into mathematics

5 Everyday calculations

5.1 Checking the receipt

Now consider some everyday situations in which a calculator is handy. Start with a familiar item, namely an old till receipt from a shop – perhaps found in the bottom of a cupboard.

Exercise 5: Detective work

The shop receipt contains a great deal of information and tells its own story. Imagine you are playing detective. How much information can you find – look for the where and when and what of the transaction.


The transaction was at Carolan's in Milton Keynes on 18 Aug 1995 just after 11.46, when a gadget and an apron were purchased using a £10 note (or two £5 notes). The change given was 55p.

There are other gems of information contained on the receipt, including some mathematical ones.

First is the basic arithmetic correct?

Set your calculator to display two decimal places and use it to check:

  • the adding up to give the subtotal and

  • the subtraction to give the change.

Both are correct.


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