Why don't astronomers use everyday units to measure distances (what is an AU or a pc)? (Intermediate)
How this formula works: The WEEKNUM function takes two arguments, a date, and, optionally, an argument called return_type, which controls the scheme used to calculate the week number. See the WEEKNUM page for more information. B4 contains a date value for January 5, 2016. The DAY function returns the number 2 representing the calculated week number. Note that by default, the WEEKNUM function uses a scheme where week 1 begins on January 1, and week 2 begins on the next Sunday (when the return_type argument is omitted, or supplied as 1).
For example, if you want to display days of week as the first 2 letters, enter them as value arguments in the CHOOSE function: =CHOOSE(WEEKDAY(A2),Su,Mo,Tu,We,Th,Fr,Sa). In this formula, the Excel WEEKDAY function gets the day of week as a serial number. And the CHOOSE function uses that number as index_num (the 1 st argument) that indicates which value from the list of value arguments to return.