Thread: Four Nines View Single Post 2007-02-01, 19:47 #1 petrw1 1976 Toyota Corona years forever!   "Wayne" Nov 2006 Saskatchewan, Canada 2×3×773 Posts Four Nines I don't know if this a new one for some of you OR as old as Mersenne himself and I hope I am not told again that it has been done. None of the links to other websites from the four-fours types of puzzle that I have seen yet have dealt with four-nines. The Four 9's Puzzle: For you Disney fans this puzzle is also known as: "The 101 Damn Calculations". Using four 9's and standard mathematical operations formulate equations with the answer being each of the numbers from 0 to 100. All 101 (a prime number!!!) are possible. Every calculation MUST use exactly four 9's and no other digits. The allowable operations are: · Addition: 9 + 9 = 18 · Subtraction: 9 – 9 = 0 · Multiplication: 9 * 9 = 81 · Division: 9 / 9 = 1 · Parenthesis: (9 + 9) / 9 = 2 · Square-root: √9 = 3 · Factorial: √(9!) = 6 · Exponential: √9^√9 = 27 · Concatenation: 99 · Decimal Point: .9 OR 9 . Some puzzles of this form allow the use of repeating decimals, my version does not required or allow it: I think using .9 repeating as 1 makes this puzzle too easy. . Other versions allow the percent operator (i.e. √9% = .3). Again it is not necessary for this puzzle but if you have to use it.....  