Prefixes in Math

Prefixes in Math What are the prefixes for 7, 8, 9, and 10? Which prefixes are you referring to? There are actually at least two sets of number prefixes in English, derived from Latin and Greek. The Latin are used (a little modified) in names for large numbers: Large Numbers and Infinity - Dr. Math FAQ http://mathforum.org/dr.math/faq/faq.large.numbers.html Decillion, Vigintillion, Trigintillion... - Dr. Math Archives http://mathforum.org/dr.math/problems/trichardt12.10.98.html The Greek forms are used in names of polygons: Naming Polygons and Polyhedra - Dr. Math FAQ http://mathforum.org/dr.math/faq/faq.polygon.names.html Here is a list of them: Number Greek Latin ------ ----- ----- 1 mono- uni- 2 duo-/di- duo-/bi- 3 tri- tri- 4 tetra- quad- 5 penta- quint- 6 hex- sex- 7 hept- sept- 8 oct- oct- 9 ennea- non- 10 dec- dec- 20 icosa- vigint- 30 triaconta- trigint- 40 tetraconta- quadragint- 50 pentaconta- quinquagint- 60 hexaconta- sexagint- 70 heptaconta- septuagint- 80 octaconta- octogint- 90 enneaconta- nonagint- 100 hect - cent- I haven't found all of these in dictionaries; the higher ones are taken straight from Latin or Greek rather than from standard English prefixes, and many have several variants. (You can find the teens in the pages I cited.) You may enjoy looking them all up in a dictionary to see what words use them. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/