Copyright © University of Cambridge. All rights reserved.

'Calcunos' printed from http://nrich.maths.org/

Show menu


Some time ago I was walking past a garage. Down on the ground was the big sign that they have that tells motorists how much the petrol will cost. You've probably seen them yourselves and you may have been asked to look out for the cheapest petrol around. The signs usually tell you the price for the different kinds of petrol. Since we measure in litres it's the price for one litre.

Well, this sign was being prepared to be put up by the side of the garage. I went over and looked at the part that shows the price. I was interested in how the numbers were shown and how they altered when the price changed. This particular one, like so many, showed the numbers like they are on a calculator display.

The little lines on a calculator display can be called 'light bars'. This is how they generally look for the figures 0 through to 9:-

pic1


In this sign they were brightly coloured flaps which on one side showed the colour and on the other side were blank. As I walked away from the garage I got thinking. This is the challenge that came to my mind.

If we had 16 light bars we could only make certain numbers. For example:-

pic2


So, my challenge to you is to find all the numbers you can make, using 16 light bars all the time and forming the figures in the same way as I did them for 0 to 9.


When you've done a few you may be able to think of a method or system for helping you along the way. When you do, do write and let us know what it was, as well as sending us your solutions.

The last word, as usual, is to say when you are happy with what you have got, "I wonder what would happen if ...?''