the decimal place-value system
0 and infinity
pi
Brahmagupta
negative numbers
unknowns in equations
trigonometry
Al-Khwarizmi
algebra
Pythagoras
right-angled triangles
the harmonic serie
Euclid
300BC "The Elements": axioms
Archimede
calendar
religion: Nile river god Hapi
measuring device
landmeasure
measure unit
legth and area calculation
decimal system
binary counting system
fractions
Eye of Horus: geometric theory
accurate value of pi
Pyramid - the golden ratio, right angle