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

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All Questions Answers
Score Newest
answer
79
Prove that the equation $x^2-y^2 = 2002$ has no integer solution
Mar 17, 2017
answer
54
How many subsets of set $\{1,2,\ldots,10\}$ contain at least one odd integer?
Jan 15, 2017
answer
52
Where does the constant increase by 2 of differences between integer square values come from?
May 7, 2015
answer
51
Every point of a grid is colored in blue, red or green. How to prove there is a monochromatic rectangle?
Sep 8, 2016
answer
50
Is there a combinatorial interpretation of the triangular numbers?
Oct 18, 2017
answer
42
How many pairs of numbers are there so they are the inverse of each other and they have the same decimal part?
Feb 25, 2017
answer
33
The sum of the squares is less than or equal to the square of the sums for all $n$
Mar 8, 2015
answer
30
How do I find the diameters of the circles in this geometry puzzle?
Feb 12, 2017
answer
26
Proving that modular inverse only exists when $\gcd(n,x)=1$
Jan 17, 2017
answer
25
What is the sum of the $81$ products in the $9 \times 9$ multiplication grid?
Jun 11, 2016
Top Meta posts
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Advise new users to stay engaged with their question
13
Comments soliciting downvotes
5
When someone gives you -2 points
4
Underline does not display in fraction. Mathjax bug?
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Is there an English idiom for trying to do two things at the same time and failing at both of them due to splitting your effort?
23
How to build a trap to last the ages?
16
Longest word with adjacent letters on a keyboard
15
Draw the EU Estimated Sign
14
180 degree rotation matchstick equality

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