How to make simple calculation in dos prompt & make mini calculator

I am going to show how to make simple calculation in Dos prompt

Go to start > run > type cmd hit enter
Now type c:\>set /a 10+10 hit enter
You got answer 20.
Use all arithmetic operators and expressions for calculation.
See below calculation.

If you want more details type c;\>set /? hit enter.

If you want mini calculator in batch file, simply copy below code and paste to the notepad.

@echo off
:A
cls
echo Simple Calculator
set /p B=Enter the value and hit enter:
set /a C=%B%
echo %B% = %C%
pause
goto A

Save Calculator.bat
.bat is extension for batch file

Now double click that bat file, your mini calculator Is ready like below.