No matter how many years of higher math you’ve taken in college, some real-world math problems are incomprehensible…
e.g., airlines’ revised formulas for accumulating frequent flyer miles
http://www.delta.com/content/www/en_US/skymiles/2015-skymiles-program.html?icid=SM_15_announce
It’s now some byzantine algebraic calculation that depends on the cabin class of the ticket, whether you paid full fare, which credit card you used, and what the alignment of Venus and Mars was on the day you booked the ticket.