The difference is zero if you aren't insinuating that the term, "multiple" doesn't involve exponential factors.
3•4 = 12
4•3 = 12
12
-12
___
0
However, if you are saying one multiple of 3 involves exponential powers, Then 3^4 is 81 and 4^3 is 64
4^3 = 64
64 - 81 = -17
