title: determining average grades and displaying letter grades
body: <p>I'm working on a program for class that finds the average of 5 entered test scores then displays the letter grades relevant to each letter score. letter score is a 10 point system ( A = 90-100 B = 80-89, etc)</p>
  
  <p>This is what I've put together so far but it doesn't seem to recognize "avg" in the syntax. any suggestions? </p>
  
  <pre><code>def main():
      while true:
          grade = int(input('Enter grade: '))
          total += grade
          avg = calc_average(total)
          abc_grade = determine_grade(grade)
  
          print('Average grade is: ' avg)
          print('Letter grades for entered grades are: ' abc_grade)
  
      def calc_average(total):
         return total / 5
  
      def determine_grade(grade):
          if grade &gt;= 90 and &lt;= 100:
              return 'A'
          elif grade &gt;= 80 and &lt;= 89:
              return 'B'
          elif grade &gt;= 70 and &lt;= 79:
              return 'C'
          elif grade &gt;= 60 and &lt;= 69:
              return 'D'
          else:
              return 'F'
  
  main()
  </code></pre>