The two-daughter-problem
70851
In a family with two children, what are the chances, if one of the children is a girl, that both children are girls?
137515
Understanding the "Birthday Problem"
79485
Problem with solving systems of linear congruence of two variables
87431
$n-$circular arrangement problem
48692
A problem about the graph theory
144571
A conjecture including binomial coefficients
107964
Simple combinatorics problem.
101804
Problem concerning the use of Pigeonhole (Box) principle
14783
A Number Theory problem (GCD)
126297
A high school Olympiad problem
10724
Case of the 'mice problem' for $n=3$
129693
An interesting problem with "decomposing" natural numbers.
96086
Double Factorial: Number of possibilities to partition a set of $2n$ items into $n$ pairs
146933
Proving bipartition in a connected planar graph
377
Problem involving many squares and several variables.
32181
A logic puzzle involving a balance.
158534
Proof that any linear system cannot have exactly 2 solutions.