Какие ж, оказывается, интересные штуки знает CMD.EXE!

Here is a little known feature of our beloved CMD.EXE. It is extremely easy to evaluate an arithmetic expression! All it takes is a five characters. Just type set /a followed by your expression.

Here is an example:

E:\>set /a 1+1
2

Or, if you want, you can convert hex numbers to decimal:

E:\>set /a 0x8000ffff
-2147418113

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