There is no formula in any cell of Column C in the Forum spreadsheet, just constant values (5, 6 or 7). On the other hand, they are the "weekday ordinals" for the dates given in Column A (those with April 1, 2010 have 5 -- and April 1, 2010 fell on a Thursday -- while those with April 2, 2010 have 6 -- Friday -- and those with April 3, 2010 have 7 -- Saturday). However, there are no IF() formulae.