Well, I remember back in those days I wrote a quadratic equation solver in C. I spent more time on the text-based interface than I did on the actual calculator. If you want that particular project to take more than 20-30 minutes (in C, probably 5 minutes in Python), than I would suggest using no other library than the standard I/O library (if you are using C, which I highly recommend) and writing the square root function(s) yourself. Although, if you want a genuine programming club (maybe wait until high school?) I would strongly suggest that you DO NOT start out with games and DO NOT encourage people to join on the premise that you will be making some type of game. That way, it can be a PROGRAMMING club, not a GAMES club. If you have a "games club", or anything similar to it, you might as well be wasting your time during all club-related activities, trust me. I would, if I were you, orient the club towards mathematical formulas implemented in C without the use of math functions. IMHO, that is the best way to start out programming. Check out Project Euler if you want club challenges, and good luck. Maybe you can make an impression on a child or yourself that is positive of programming, and real programming at that.

Yes, this. In any case, you must learn programming before learning game programming (unless you want to use Game Maker for the rest of your life). Without knowing programming, "game development" is little more than following tutorials you barely understand, and never learning anything. And since programming is the base skill (along with mathematics) it will be a) more useful and applicable, to specialize and whatnot, b) better accepted as a skill, c) more likely to draw in people with varied interests.