C:\temp>set /a 100-24
76

Works!


C:\temp>set /a 36295495680-2743
Invalid number. Numbers are limited to 32-bits of precision.


Woops, too big.

I google for "subtract.bat" which nets me this
http://members.cox.net/tglbatch/batch/subtract.bat

But I can't make that work, I save it to my disk and try to run it and it barfs on me. I'm not sure why. Something's wrong with it, perhaps it was written for an older version of DOS and won't work on Vista or Server2003 (the environments I need to perform the subtraction in). Or perhaps its formatting is screwed up and I can't figure out how to fix it. And anyway, it was written to accept only 8 characters so it's not really useful anyway.

I suppose I could go to a higher level language, but I love solving things in simple batch files when I can.

Anyone got other ideas?

NOTE: Calling out to a windows EXE or some other kind of EXE to get results is fine, as long as that EXE ships with windows by default.