This is a great question! Most passenger cars have two axles that are turning the wheels, while larger vehicles may have three or more.
If you want to tell how many axles a vehicle has, look at the number of wheels—two sets of tires equal two axles. As you will most likely learn in class, the mechanical requirements and amount of drive force needed to move the vehicle will determine the number of axles and tire sets.
Hope this helps, and best of luck with trade school!