The Greek numerical prefixes are used for naming things like polygons, polyhedra and polynomials::
- mono = 1
- di = 2
- tri = 3
- tetra = 4
- penta = 5
- hexa = 6
- hepta = 7
- octa = 8
- ennea = 9
- deca = 10
- hendeca = 11
- dodeca = 12
- triskaideca = 13
- tetrakaideca...enneakaideca = 14...19
- icosa = 20
- icosikaihena = 21
- icosidi...icosiennea = 22...29
- triaconta = 30
- tetraconta...enneaconta = 40..90
- hecto | hecato = 100
- chilia = 1000
- myria = 10000
The word "kai", meaning and, is often omitted. Chemistry uses a slightly different set of prefixes, two of which come from latin::
- nona = 9
- undeca = 11
And the rest of which are pretty much made up::
- henicosa = 21
- docosa...nonacosa = 22...29
- hentriaconta...nonatriaconta = 31...39
- kilia = 1000
- dilia...nonalia = 2000...9000
And, finally, for large numbers these prefixes are used:
- bi = 2
- tri = 3
- quadra = 4
- quinta = 5
- sexta = 6
- septa = 7
- octo = 8
- nona = 9
- deca = 10
- undeca = 11
- dodeca = 12
- tredeca = 13
- quattuordeca = 14
- quinquedeca = 15
- sexdeca = 16
- septendeca = 17
- octodeca = 18
- novemdeca = 19
- viginti = 20
- unviginti...novemviginti = 21...29
- triginti = 30
Some of these suffices need checking, since these are not quite the latin names of the numbers...but in the actual compounds (e.g. octillion, vigintillion) they disappear.
See also ReallyBigNumbers