U simply add all the six numbers and divide by it . when you add all the test scores you get 407.6 . Next you divide that by 6 since there were 6 tests taken and the test avg is 81.46 which falls under b category for grades provided from the table
All you need to do here is add all the answers up and divide them by the number of how much answers there where. Example: #3: 2.5+4.6+6.7+4.8=18.6 . 18.6/4=4.65 hope I helped
