title: shell script + numbers sum
body: <p>what the best simple elegant way to sum number in ksh or bash
  my example is about let command , but I want to find better way to summary all numbers</p>
  
  <p>for example</p>
  
  <pre><code>num1=1232
  num2=24 
  num3=444
  .
  .
  .
  
  let SUM=$num1+num2+num3.........
  </code></pre>