title: Grading program having problems with while loop and using different data types
body: <p>I'm making a program where I need to have the user input a series of homework grades (ranging from 0 to 10) until they type 'done' in which case I must calculate the average of the scores and provide a corresponding letter grade. My trouble is, I don't know how to calculate the average when I don't have the exact number of homeworks to divide the sum of all of the homeworks by, since it's not on a finite loop. And also, when I run my program I keep getting an error message that says TypeError: unorderable types: str() &lt; int()</p>
  
  <p>Here's my code so far:</p>
  
  <pre><code>    print("Enter your homework scores one at a time, must be an integer ranging from 0 to 10. When finished, type done.")
  number=input("Enter your homework grade: ")
  
  while number != 'done':
      number=input("Enter your homework grade: ")
      percentage= number*10 #I need to divide by number of homeworks there are, but I'm not sure how to get the variable I need to divide by.
  
      if number &lt; 0 or number &gt; 10:
          print("Score must be between 0 and 10")
      elif percentage &gt;= 92 and number &lt; 100:
          letter = 'A'
      elif percentage &gt;= 87 and number &lt; 92:
          letter = 'B+'
      elif percentage &gt;= 80 and number &lt; 87:
          letter = 'B'
      elif percentage &gt;=77 and number &lt; 80:
          letter = 'C+'
      elif percentage &gt;=70 and number &lt; 77:
          letter = 'C'
      elif percentage &gt;= 67 and number &lt; 70:
          letter = 'D+'
      elif percentage &gt;= 60 and number &lt; 67:
          letter = 'D'
      elif percentage &lt; 60 and number &gt;= 0:
          letter= 'F'
      elif number == 'done':
          print(percentage,"%, you got an ", letter)
      else:
          print("Error: please enter an integer ranging from 0 and 10.")
  </code></pre>