(00:08) Problem introduction.
(00:33) How to use NETWORKDAYS.INTL to count the number of working days between a start and end date. NETWORKDAYS.INTL is in Excel 2010 or later versions.
(01:46) Formula to count the number of Mondays & Tuesdays since birth with NETWORKDAYS.INTL and TODAY functions.
(02:21) Create custom weekend / weekday pattern (dates to count / dates to not count) using a seven digit text string were zero = weekday and one = weekend.
(03:28) Array Formula to count the number of Mondays & Tuesdays since birth with SUMPRODUCT, WEEKDAY, ROW, INDIRECT functions.
(03:42) Learn how to create a “Dynamic Variable-Length Array of Sequential Numbers”. This formula element has a section in Chapter 7 of the book Ctrl + Shift + Enter, Mastering Excel Array Formulas.
(07:04) Array Formula to count the number of Mondays & Tuesdays since birth with SUMPRODUCT, TEXT, ROW, INDIRECT functions.