Problem from Kenneth Rosen's Discrete Mathematics and its Applications, Section 1.8
106827
Proof for two sequences producing the maximum value when sorted
129693
An interesting problem with "decomposing" natural numbers.
41726
Musical and combinatorial proof
134440
An unexpected application of non-trivial combinatorics
111954
Computing the cardinality of a combinatorial set
111032
Proof of Sets involving the Cartesian Product
63571
The Mississipi counting problem, this time in circle
36747
$\text{Tor}_0^R(M,N)\simeq M\otimes_R N$
62996
A problem regarding the proof of ${p^nk\choose p^n}\equiv k\mod p$, where $p\nmid k$.
114277
Proving in Discrete Structures Problem that $2^N = \binom{N}{0} + \binom{N}{1} + \binom{N}{2} + \dots + \binom{N}{N}$
10724
Case of the 'mice problem' for $n=3$
110876
Prove that $p\mid \binom{p}{k},\ 0< k< p$
25553
elementary set theory (cartesian product and symmetric difference proof)
96903
How to show via inductive proof (and without the use of the binomial theorem) that $ {n\choose k} \in \mathbb{N} $?
66019
Revisited: Binomial Theorem: An Inductive Proof
959
Prove that ${{n}\choose{k}} = {{n - 2}\choose{k}} + 2{{n - 2}\choose{k - 1}} + {{n - 2}\choose{k - 2}}$.
24212
proving how many permutations exist.