Propeller aerodynamics are extremely complicated, but there are some overall aspects that you can accept as fact without actually becoming an expert in props. First off the velocity of the blade is very low at the root, and very high at the tip. The maximum RPM that a prop can turn efficiently is limited by the velocity at the tip. The tip velocity cannot exceed roughly .9 mach without creating a bunch of drag, and a bunch of noise. The propeller is twisted to optimise it for a certain airspeed. As airspeed increases thrust decreases. A prop is just a wing, and if you look at one station (diameter) of a prop you could calculate the lift (thrust) using conventional math. But, the volocity and angle of attack will be different at every other station, so you would have to do dozens of calculations to come up with the total lift (thrust) at a given airspeed. Want to know the thrust at a different airspeed, do it all over again. It's best to let the computer do all of that for you and use a prop calculator... This one seems pretty good:
http://www.gylesaero.com/_frames/f_propcalc.shtml
Ty