the decimal place-value system

0 and infinity

pi

Brahmagupta

negative numbers

unknowns in equations

trigonometry

Al-Khwarizmi

algebra

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

Pythagoras

right-angled triangles

the harmonic serie

Euclid

300BC "The Elements": axioms

Archimede