Top network posts

• 78 Prove that the equation $x^2-y^2 = 2002$ has no integer solution
• 53 Where does the constant increase by 2 of differences between integer square values come from?
• 51 How many subsets of set $\{1,2,\ldots,10\}$ contain at least one odd integer?
• 47 Every point of a grid is colored in blue, red or green. How to prove there is a monochromatic rectangle?
• 45 Is there a combinatorial interpretation of the triangular numbers?
• 41 How many pairs of numbers are there so they are the inverse of each other and they have the same decimal part?
• 31 How do I find the diameters of the circles in this geometry puzzle?
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