Create 4 functions that use a parameter and return
-will create a list of test scores
* entering each score into a list individually (use 3 test scores and assume tests have a max score of 40)
print the scores entered
print the average test score
print the letter grade using these parameters
A 90 - 100
B 80 - 89
C 70 - 79
D 60 - 69
F Below 60