A combinatorial argument for IMO 1972, Problem 3.
56474
An example where $\frac{(2m)!(2n)!}{m!n!(m + n)!}$ is the number of ways of counting something?
117775
Combinatorial proof of a Stirling number identity.
129693
An interesting problem with "decomposing" natural numbers.
143573
Problem (1.8) A Path to Combinatorics Solution Verification.
41726
Musical and combinatorial proof
10272
A three-way duel (probability puzzle)
125174
Combinatorial intuition of identity
46580
Variation on the Monty Hall Problem
11824
A maximization problem
75225
Exercise $ 3.4.15 $ of David Marker’s “Model Theory”.
126297
A high school Olympiad problem
104603
Integer program in which at least one of three inequalities holds
154841
Computing symmetry/combinatorial factor for a diagram in $\phi^4$ theory
61483
Prove the following identity combinatorially
90519
Combinatorial proof of $\sum\limits_{k=0}^n {n \choose k}3^k=4^n$
68882
Path to Combinatorics Problem [$1.11$]
26343
Number of certain (0,1)-matrices, Stanley's Enumerative Combinatorics