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2 + 2 = 5 (Posted on 2008-09-16) Difficulty: 3 of 5
Using only two 2s and any of the standard mathematical symbols, write an expression whose value is equal to 5.

An approach could be: sqrt((2 * 2)!) = 4.90

Standard mathematical symbols (for this problem) are: addition, subtraction, multiplication, division, exponentiation, square root, factorization, parenthesis, positive, negative, ln, log. Superfactorials and such are not excluded, but not part of the desired solution. Any symbol having a value of its own, such as e, pi, and infinity, is not authorized.

  Submitted by Leming    
Rating: 4.0000 (1 votes)
Solution: (Hide)
While understanding that exotic functions like "floor" and "ceiling" make this an easy problem (and are all correct), here is a solution using routine math symbols:

(sqrt(.2))^-2 = 5

Comments: ( You must be logged in to post comments.)
  Subject Author Date
re: Puzzle AnswerK Sengupta2023-08-09 09:47:44
Puzzle AnswerK Sengupta2022-06-06 20:59:10
QuestionDoes these count?Dej Mar2008-09-17 00:56:15
This one seems too simple to be correctcyclothymic2008-09-16 15:32:32
Solutionno ceiling...pcbouhid2008-09-16 14:06:01
Solutionsome solution(s)Dej Mar2008-09-16 11:16:02
SolutionA simple modification -- trivial solutionCharlie2008-09-16 10:48:11
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