Almost every class uses a grade book. Using the grade scale in Table 1a, calculate students grades first using one spilling IF() formula and then one spilling IFS() formula in worksheet Grades. The highest possible percentage is 100%. Then using the grade point values in Table 1b, use one spilling SWITCH() formula and map the grades to a point code. Tally the number of As, Bs, etc. earned. Use the SORT() and UNIQUE() function to create this tally as shown in the fiqure 2.