Let me see if I understand your question:
101=50-h
this would just be an equation with a variable: this variable is "h". Variable is an unknown value, like a name for "something".
so we could say that 101 equals 50 minus "something" and we call this something "h"
this is what 101=50-h "means"
as it happens, we can find out the value of this h:
we can subtract 50 from both sides of the equation:
101-50=50-50-h
51=-h
and multiply by (-1)
-51=h
so our h is equal to -51.
so... does not actually mean here 49...
let me know if you have further questions!