--- Introduction ---

In fact this notion is not so difficult as it often appears to some students, and it is in practicing that one becomes expert. Therefore we gather here 11 training exercises on this notion, in a hope to quickly make you an expert on it. The most recent version

**
This page is not in its usual appearance because WIMS is unable to recognize your
web browser.**

Please take note that WIMS pages are interactively generated; they are not ordinary HTML files. They must be used interactively ONLINE. It is useless for you to gather them through a robot program.

Description: collection of training exercises on necessary and sufficient conditions. interactive exercises, online calculators and plotters, mathematical recreation and games

Keywords: interactive mathematics, interactive math, server side interactivity, logic, necessary,sufficient