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Mathematics
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Joffan

Interested in mathematical counting puzzles and many others ${\overset\infty \smile}$

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  • Member for 4 years
  • 2,358 profile views
  • Last seen Dec 11 '18 at 17:04

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Top Posts (1,470) All Questions Answers | Votes Newest

75 Prove that the equation $x^2-y^2 = 2002$ has no integer solution Mar 17 '17
53 Where does the constant increase by 2 of differences between integer square values come from? May 7 '15
48 How many subsets of set {1,2,…,10} contain at least one odd integer? Jan 15 '17
44 Every point of a grid is colored in blue, red or green. How to prove there is a monochromatic rectangle? Sep 8 '16
42 Is there a combinatorial interpretation of the triangular numbers? Oct 18 '17
41 How many pairs of numbers are there so they are the inverse of each other and they have the same decimal part? Feb 25 '17
30 How do I find the diameters of the circles in this geometry puzzle? Feb 12 '17
25 What is the sum of the $81$ products in the $9 \times 9$ multiplication grid? Jun 11 '16
22 Which of the following numbers is greater? Feb 23 '17
22 Prove that the expression is a perfect square May 19 '17
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