Assign a final letter grade to each of the students listed in the worksheet in Example 2.4 (see Fig. 2.23). Base the letter grades on the following rules: Overall Score Grade 90 and above A 80 to 89.9 . . . B 70 to 79.9 . . . C 60 to 69.9 . . . D Below 60 F The letter grade conversion can easily be carried out with the following formula, which utilizes several nested IF functions: =IF(E2 >= 90, "A", IF(E2 >= 80, "B", IF(E2 >= 70, "C", IF(E2 >= 60, "D", "F")))) This formula assumes that cell E2 contains the numerical score being converted, as shown in Fig. 4.1. The formula itself appears in cell F2. The formula is copied into cells F3 through F8, to accommodate all of the remaining students. Sometimes the use of deeply nested IF functions may be circumvented by the clever use of formulas. For example, it may be possible to decompose a complicated set of if-then-else conditions into two or more subsets, and then combine the results after the logical outcome of each subset has been determined. Example 4.2 illustrates one such procedure.