Ah, you are programming in C/C++. That's the language QB64 translates your BASIC code into. In other words, QB64 is a translator.
I doubt you would need huge numbers in gaming, so whatever the fastest method is would be the best choice. There are little speed testing programs you can use. Mark and Steve have made quite a few of those.
I mean for me, on a fairly slow system, this happens almost instantaneously...
j = j + .1
PRINT "Hello world.", i
, j
It also shows how computers can't count, without a coded system of counting.
So if 10 conditions were used with a string math calculation, I suppose you could estimate a performance of a 1 to 10 thousand digit number being calculated in a very short amount of time. Over kill for business apps, great for scientific apps, and I don't do gaming, so I have no experience to offer an opinion on adequate speed over some alternate method, in that regard.
Pete