What does 101=50-h h means the number 49

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!