How to write Egyptian numbers
By about 3000 BC, the ancient Egyptians had ways to write down numbers. They made one vertical line for one, two vertical lines for two, and so on up to nine. This is the same as earlier African number systems using tally sticks. For ten, the Egyptians made a U-shaped mark that represented the yoke of an ox, and for twenty you made two of the U-shaped marks.
How to write bigger numbers
For 100, the Egyptians drew a coil of rope, and for 1000 they drew a lotus flower. They used a finger to show 10,000 and a tadpole to show 100,000, because when the Nile river flooded and the waters went down there would be millions of tadpoles everywhere.
The Egyptian system of writing numbers worked great as a way to write down big numbers, but it was hard to use for multiplication and division. That’s why everyone was enthusiastic about Arabic numbers when they came along.
Egyptian geometry and quadratic equations
But even using these early Egyptian numbers, Egyptian engineers understood a lot about math. Certainly by the time of the Middle Kingdom (about 1800 BC), Egyptian mathematicians knew that the Pythagorean Theorem was true – the squares of the sides of a right triangle equal the square of the hypotenuse – and they used it to design buildings. They knew how to calculate the value of pi (they got it as accurate as 3.16) and they used pi to figure out the area of circles and the volume of cylinders. Egyptian mathematicians also knew how to calculate square roots, and they could solve equations involving squares.
Learn by doing: try to write other numbers in Egyptian
More about African numbers
Bibliography and further reading about Egyptian science:
Science in Ancient Egypt, by Geraldine Woods (1998). Easy reading.
Technology in the Time of Ancient Egypt, by Judith Crosher (1998). Also for kids. Includes some activities for kids to try at home or at school.