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Apr
4
Fun Holiday – Square Root Day

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.

Celebrate mathematics on Square Root Day.
Celebrate mathematics on Square Root Day.
©bigstockphoto.com/Wavebreak Media Ltd

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.

Rare Dates

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:

  • February 2, 2004 (02/02/04): 2 X 2 or 2² = 4
  • March 3, 2009 (03/03/09): 3 X 3 or 3² = 9
  • April 4, 2016 (04/04/16): 4 X 4 or 4² = 16
  • May 5, 2025 (05/05/25): 5 X 5 or 5² = 25
  • June 6, 2036 (06/06/36): 6 X 6 or 6² = 36
  • July 7, 2049 (07/07/49): 7 X 7 or 7² = 49
  • August 8, 2064 (08/08/64): 8 X 8 or 8² = 64
  • September 9, 2081 (09/09/81): 9 X 9 or 9² = 81

Other Mathematical Holidays

You don't have to wait for Square Root Day to celebrate a unique mathematical holiday. There are several other mathematical holidays throughout the year that honor mathematicians and their work. Some of these include Pythagorean Theorem Day, e-Day, Pi Day, Tau Day, Yellow Pig Day, Pi Approximation Day, and Fibonacci Day.

How to Celebrate?

  • Learn more about the real-life and mathematical applications of square root.
  • Eat square shaped food, made specifically from root vegetables the whole day. May we recommend square sweet potato fries, square potato gratin, and a square carrot cake.
  • Spend the day learning about other special date patterns. Use our Date Pattern Calculator to find out when's the next Sequential or Palindrome Day.

Did You Know...

...that the symbol for square root (√) is called the radix or the radical sign and was first used in print in 1525?

Square Root Day Observances

Fun Holiday: Square Root Day Observances
YearWeekdayDateName
2025MonMay 5Square Root Day

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January 2016
SMTWTFS
     12
3456789
10111213141516
17181920212223
24252627282930
31      
February 2016
SMTWTFS
 123456
78910111213
14151617181920
21222324252627
2829     
March 2016
SMTWTFS
  12345
6789101112
13141516171819
20212223242526
2728293031  
SMTWTFS
     12
3456789
10111213141516
17181920212223
24252627282930
May 2016
SMTWTFS
1234567
891011121314
15161718192021
22232425262728
293031    
June 2016
SMTWTFS
   1234
567891011
12131415161718
19202122232425
2627282930  
July 2016
SMTWTFS
     12
3456789
10111213141516
17181920212223
24252627282930
31      
August 2016
SMTWTFS
 123456
78910111213
14151617181920
21222324252627
28293031   
September 2016
SMTWTFS
    123
45678910
11121314151617
18192021222324
252627282930 
October 2016
SMTWTFS
      1
2345678
9101112131415
16171819202122
23242526272829
3031     
November 2016
SMTWTFS
  12345
6789101112
13141516171819
20212223242526
27282930   
December 2016
SMTWTFS
    123
45678910
11121314151617
18192021222324
25262728293031

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