The second full week of the year has several interesting dates, all for different reasons.

Wednesday, 1/14/15, is an addition day, since 1 + 14 = 15

Thursday, 1/15/15, and a multiplication day, since 1 * 15 = 15

Friday, 1/16/15, is a Minus subtract day, since 1 – 16 = -15

And don’t forget that 1/15/15 is also a Reverse Division day since 15 / 1 = 15.  This always happens when one of the factors of a multiplication day is 1.