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Prefixes in Math

Date: 08/21/2001 at 21:13:30
From: anthony
Subject: Wondering about prefixes

What are the prefixes for 7, 8, 9, and 10? 

Please help.

Date: 08/22/2001 at 09:23:24
From: Doctor Peterson
Subject: Re: Wondering about prefixes

Hi, Anthony.

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   

   Decillion, Vigintillion, Trigintillion... - Dr. Math Archives   

The Greek forms are used in names of polygons:

   Naming Polygons and Polyhedra - Dr. Math FAQ   

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   
Associated Topics:
Elementary Large Numbers
Elementary Number Sense/About Numbers
Middle School Number Sense/About Numbers

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