Step 1: Request the user to input a grade and assign it to a variable named grade.

grade = input("Enter a grade: ")

Step 2: Convert the variable grade into an integer.

• Note: Add the command int() to the code line from step 1.

grade = int(input("Enter your grade: "))

Step 3: Create a condition that checks if the grade is equal to or higher than 90 and if so, print A.

if grade >= 90:
   print("A")

Step 4: Continue the condition to check if the grade is equal to or higher than 80, and if so, print B.

elif grade >= 80:
    print("B")

Step 5: Continue the condition to check if the grade is equal to or higher than 70, and if so, print C.

elif grade >= 70:
    print("C")

Step 6: Continue the condition to check if the grade is equal to or higher than 65, and if so, print D.

elif grade >= 65:
    print("D")

Step 7: Continue the condition to check if the grade is equal to or higher than 0, and if so, print F.

elif grade >= 0:
    print("F")

Step 8: Finally, the code should print an error message if the user inserted an invalid number, such as a negative number.

else:
    print("ERROR: Grades cannot be negative numbers or words.")

Final Code

# explains purpose of the script
print("This program will calculate and display the letter grade of a numerical value\n")

grade = float(input("Enter a grade: "))

if grade >= 90:
    print("Letter grade: A")
elif grade >= 80:
    print("Letter grade: B")
elif grade >= 70:
    print("Letter grade: C")
elif grade >= 65:
    print("Letter grade: D")
elif grade >= 0:
    print("Letter grade: F")

# Will be printed if the value is a negative number or a word.
else:
    print("ERROR: Grades cannot be negative numbers or words.")
# prevents program from closing upon execution
input("\nPress 'Enter' to exit the program")