The Eye of Horus [wiki] is a powerful Egyptian symbol used as protection from evil. Indeed, the "Rx" symbol used in medicine has its origin in the Eye.
But did you know that the Eye of Horus was used to count fractions?
The Eye of Horus fraction system was based on the Eye of Horus symbol. This system was used to record prescriptions, land and grain.
Fractions are created by combining sections of the Eye of Horus symbol. Each section has a different value. The complete Eye of Horus with all parts in place has a value of 1. In reality the complete Eye of Horus represents 63/64, which is rounded off to 1.
The system is based on halves. Half of 1 equals 1/2, half of 1/2 equals 1/4 and so on until the smallest value of 1/64. By adding together the values of different sections fractions are created.