uni-, mono-: one duo-, bi-: two tri-: three
quad-,quart-: four pent-, quin-: five sex-: six
sept-: seven oct-: eight non-: nine
dec-: ten cent-: hundred
* A bicycle with one wheel is a unicycle..
* A magazine that appears twice a month is bimonthly..
* A flag with three colors is a tricolor flag..
* To make something four times as great is to quadruple it..
* A shape with five sides is a pentagon..
* A person who is in his/her sixties is a sexagenarian..
* A ten-event athletic contests is called decathlon..