Square Root Day is celebrated on a day where the first two digits in the date are the square root of the last two digits. Only date formats that have the month and date first and the last two digits of the year last (mm/dd/yy, m/d/yy, dd/mm/yy or d/m/yy) can have Square Root Days.
Ron Gordon, a high school teacher in the State of California, United States is credited as the creator of this unofficial holiday. The first Square Root Day ever was celebrated on September 9, 1981 (09/09/81).
Opposite to Squaring
An important mathematical concept, the square root of any number (x) is equal to the number (y) that when multiplied by itself or squared returns the first number (x). In other words, the square root of x is y, because x X x or x²2 is y.
To make it clearer, let's take an actual number example: the square root of 25 is 5, because when we multiply 5 by itself (5 X 5) or square it (5²), we get 25.
Only 9 dates every century qualify to be a Square Root Day. The first day of the 21st century, January 1, 2001 (01/01/01) was a Square Root Day. Other past and future Square Root Days in this century are: