Mechanical systems
Mechanical advantage is output force divided by input force, and whatever force a machine gains it pays back in distance.
A worked example
A pulley system lifting a 450 N load with a 90 N pull has a mechanical advantage of 450 / 90 = 5, so the rope must be pulled five times as far as the load rises.
The mistake people actually make
Mechanical advantage and efficiency are different questions. A machine can multiply your force five times and still lose most of the energy you put in as heat from friction.