title: Python: Convert a Letter Grade to its corresponding integer value
body: <p>I am attempting to troubleshoot the errors in this code.</p>
  
  <p>The program is supposed to handle as many students as the user indicates are in the class. Receive a letter grade: A, B, C, D, F for each student. Finally it will calculate and display the class average. </p>
  
  <p>My code so far:</p>
  
  <pre><code>students = int(input('How many students: '))
  total_sum = 0
  for n in range(students):
      Letter = input('Enter grades: ')
      Letter_int = Letter
  if Letter == "A":
      Letter_int == int(80)
  elif Letter == "B":
      Letter_int == int(70)
  elif Letter == "C":
      Letter_int == int(60)
  elif Letter == "D":
      Letter_int == int(50)
  elif Letter == "F":
      Letter_int == int(40)
      total_sum += Letter_int
  avg = total_sum/students
  print('Average of this/these', students, 'student(s) is:', avg)
  </code></pre>
  
  <p>The code isn't adding the integer value of the letter grades, the sum always returns as 0 or TypeError: unsupported operand type(s) for +=: 'int' and 'str'. I am a python novice and I could use some assistance.</p>