How are a lever and a wheel and axle similar?

To find the Mechanical Advantage you would have to divide.

The equation for Lever is: MA = Length of effort arm
--------------------------------
Length of resistance arm


The equation for Wheel and axle is: MA = Diameter of wheel
-------------------------
Diameter of axle

OR

MA = Diameter of axle
-----------------------
Diameter of wheel


* Depending on where the force is applied.
A wheel is just like a bunch of levers arranged in a circle with the fulcrum at the center of the wheel. The axle is like the short end of the lever.One degree of rotation of the axle results in one degree of rotation of the wheel; this is just like rotating the short end of the lever to movethe long end.