— Burt Kaliski Jr. (@modulomathy) February 21, 2012
An easy one today: One sixth of the way through a 366-day leap year is exactly 61 days, a milestone reached on March 1.
In a non-leap year, the nearest day to one sixth of a year is also Day #61, but it occurs on March 2.
A leap year can be divided exactly into intervals of 3, 6, 61 and 122 days. In a non-leap year, the divisors are just 5 and 73. But there are no exact sevenths in either year, although Day #52 a special one for counting given that there are approximately 52 weeks in a year, and thus also approximately seven 52-day intervals like the one completed on February 21.