This is from https://courses.cs.washington.edu/courses/cse311/14au/slides/lecture12-filled.pdf
This property is used for modular exponentiation, that is to do a problem like this (from slide 6)
Here is the property(slide 7)
How would you go about proving this?
The first thing I did was by definition of a mod m is congruent to a modulo m,
a mod m - a = km for some integer k
What step would you take next to prove this property?