How Much Slower Will a Clock Run on the Moon? | Period of a Pendulum

Calculate the difference in period for a pendulum on the Moon versus on the Earth, then use that difference to find how much slower the clock would run on the Moon.
The hard part of this problem is understanding how to use the period on the Earth vs the period on the Moon to find get from the true elapsed time to the time a grandfather clock would report on the Moon.
This is a classic high school physics problem that often comes up when discussing Simple Harmonic Motion.