Rifle scopes can accomplish more than one thing. For one, they relieve the shooter of the worry of lining up the front sight with the rear sight and of losing focus on the target while lining up the sights. Also, of course, rifle scopes magnify the image, making hitting the target all that easier. The numbers on the scope tell you the size of the lens and how much it magnifies.
Numbers
The first number on the rifle scope signifies its magnification power. For example, a 4 X 32 sight means the scope magnifies the image four times. A 6 X 32 sight would denote a scope with a six-power magnification. Some scopes have variable magnification, which you select by turning a power ring on the scope. A 4 - 12 X 32, for example, magnifies between four and 12 times. The second number on the scope indicates the size in millimeters of the objective lens -- the one closest to the end of the barrel. So, a 4 X 32 scope would have a 32 mm lens.
Considerations
When choosing a scope for your rifle, consider that as magnification increases, brightness diminishes. At 4X magnification, the image in the scope will be brighter with a 50 mm lens than with a 32 mm lens. Bigger lenses cost more, of course, and they also weigh more. Depending on the type of hunting you do, higher magnification or brightness may not be worth the extra cost. At lower magnifications levels, a 50 mm lens won't provide a lot of extra light compared to a 40 mm lens, for example.