-: Calculations On Command Prompt :-
The command processor CMD.EXE comes with a mini-calculator that can 
perform simple arithmetic on 32-bit signed integers: 
C:\>set
 /a 2+2
4
C:\>set /a 2*(9/2)
8
C:\>set
 /a (2*9)/2
9
C:\>set /a 
"31>>2"
7
Note that we had to quote
 the shift operator since it would otherwise be misinterpreted as a 
"redirect stdout and append" operator.
For more 
information, type set /? at the command prompt.
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