Praxis the robot and Alan the "human man" lead the letter X through the development of algebra from Ancient Egypt to Rene Descartes.

Discuss the development of algebra as a practical way of solving problems. Set students calculating tasks based on text and have them first represent the problem algebraically then go on to solve it. Look at some of the examples of problems tackled by Al Khowarizmi and have students work out how to solve them.