title: assistance with my batch calculator
body: <p>Can someone tell me what is wrong with my batch script? I just doesn't work...</p>
  
  <pre><code>@echo off
  :start
  echo please enter a mathamatical equation
  set /p varia=
  set /a %varia%
  pause
  goto start
  </code></pre>
  
  <p>If you go into command prompt and type in</p>
  
  <pre><code>set /a (9*5+4-9)/10
  </code></pre>
  
  <p>the next line is</p>
  
  <pre><code>4
  </code></pre>
  
  <p>So my idea is putting it into a batch script and use variables, but no good.  I even tried just</p>
  
  <pre><code>set /a 5+5
  </code></pre>
  
  <p>but that failed too.  For some reason the cmd command doesn't work in a batch file.</p>