WEEKDAY, WEEKNUM, and YEARFRAC Date Functions

Excel's more sophisticated Date functions, WEEKDAY, WEEKNUM, and YEARFRAC on the Date and Time button's drop-down menu.

1. Use the Date Formulas worksheet in Date Function Practice.xlsx workbook file you created when doing the previous exercise.
   You will start by creating a formula in cell F3 that uses the WEEKDAY function to return the day of week of the date entered in cell E3.
2. With the cell cursor in cell F3, select the WEEKDAY function on the Date and Time button's drop-down menu. Then, click cell E3 to enter this cell address in the Serial_number argument text box and press Tab to select the Return_type text box. Then, type 2 in this text box and click OK to close the WEEKDAY Function Arguments dialog box.
   Excel returns 2 to cell F3, indicating that this date in 1949 fell on a Tuesday (when you select 2 as the return_type, 1 is Monday, 2 is Tuesday, 3 is Wednesday, 4 is Thursday, 5 is Friday, 6 is Saturday, and 7 is Sunday).
3. Use the Fill handle to copy this formula with the WEEKDAY function down to the cell range F4:F8.
   Next, you will use the WEEKNUM Date function to determine the number of the week of each date entered in the range B10:B14.
4. Click cell C10 and then select the WEEKNUM function on the Date and Time button's drop-down menu. Click cell B10 to enter this address in the Serial_number text box and press Tab and type 2 in the Return_type text box before you click OK to close the WEEKNUM's Function Arguments dialog box.
   Excel returns 7 to cell C10, indicating that February 7th fell in the 7th week of 1989 when you designate Monday as the first day of the week.
5. Copy the WEEKNUM formula in cell C10 down to the cell range C11:C14.
   Next, you will use the YEARFRAC Date function to determine what fractional part of a year the number of days elapsed between two dates represents.
6. Click C17 and select the YEARFRAC function at the very bottom of the Date and Time button's drop-down menu. Click cell A17 to enter this address in the Start_date text box. Then, press Tab and click cell B17 to enter its address in the End_date text box. Finally, press Tab and then type 3 in the Basis text box before you click OK to close the WEEKNUM's Function Arguments dialog box.
   Excel returns 0.2 to cell C17.
7. Format the result in cell C17 with the Number format on the drop-down menu attached to the Number Format command button on the Ribbon's Home tab. Use the Fill handle to copy this formula down to the cell range C18:C19.
   Now you are ready to check your formulas and their answers before you save your work.
8. Check your answers against those shown in the Date Formulas sheet in the Solved8-3.xlsx workbook file in your Chap8 subfolder in the Excel 2007 Workbook folder. When everything checks out, save your changes to the Date Function Practice.xlsx workbook (Ctrl+S) and then close the workbook.