How data is represented is an important part of computer science. There are lots of ways numbers can be represented. Choosing a good representation can make things easier or harder to do. The Ancient Egyptians had a simple way using hieroglyphs (symbols). It is similar to Roman Numerals but simpler. 

They represented numbers 1 to 9 with a hieroglyph with that number of straight lines. They arranged them into patterns (a bit like we do dots on a dice). The patterns make them easier to recognise. They used an upside down U shape for 10, two of these for 20, and so on. Their symbol for 10 also meant a “cattle hobble”. They then had a new symbols for each power of 10 up to a million. So 100 is the hieroglyph for a coil of rope.

The hieroglyph for the number 1000 was a water lily.

The hieroglyph for a million, which also rather sensible meant ‘many’, was just the hieroglyph of the god Hey who was the personification of eternity.

To make a number you just combined the hieroglyph for the ones, tens, hundreds and so on.

The Ancient Egyptian number system makes it very easy to write numbers and to add and subtract numbers. Big numbers are fairly compact, though take up more space than our decimals. It is easy to convert a tally representation into this system too. More complicated things like multiplication are harder to do. Computers use binary representation because they make all the main operations easy to do using logic. Ultimately it is all about algorithms. The Egyptians had easy to follow algorithms for addition and subtraction to go with their number representation. We have devised algorithms that allow computers to do all the calculations they do as quickly as possible using a binary representation

– Paul Curzon, Queen Mary University of London

To do…

Try doing some sums as an Ancient Egyptian would – without converting to our numbers. What is the algorithm for adding Egyptian numbers? Do multiplication using a repeated addition algorithm – to do 3 x 4 you 4 to zero 3 times.

More on..

• Lego Computer Science: Representing Numbers
• Ancient Egyptian Computer Science [PORTAL]
• Egyptian Hieroglyph Numerals Pixel Puzzles [TEACHING LONDON COMPUTING]
• More on the Ancient Egyptians [TEACHING LONDON COMPUTING]
• More on Computing and History [TEACHING LONDON COMPUTING]

An earlier version of this article first appeared on Teaching London Computing.