title: Set total equal to zero when computes the sum of given numbers
body: <p>I'm a newbie of python and I'm trying to practice some exercises, however I'm stuck with the line &quot;total = 0&quot; in this code. Actually I don't really understand why this value is initialized to 0.
  Could anyone please explain it for me ?</p>
  <pre><code>def main():
      print(&quot;This program allows you to total up some numbers&quot;)
      print()
  
      n = int(input(&quot;How many numbers do you have? &quot;))
      total = 0
      for i in range(n):
          num = float(input(&quot;Enter a number: &quot;))
          total = total + num
  
      print()
      print(&quot;The sum of the numbers is:&quot;, total)
  
  main()
  </code></pre>