Proving Least Common Multiple
1712
$ d_1,d_2\mid n\iff {\rm lcm}(d_1,d_2)\mid n\ $ [LCM Universal Property]
108742
Proving commutativity of addition for vector spaces
143540
How to prove this decomposition of sum of squares?
74523
Proof by Cases involving divisibility
151038
How to prove (A v B), (A → C), (B → D) therefore (C v D)
40848
$a\mid b,c\mid d\Rightarrow\,\gcd(a,c)\mid \gcd(b,d)$
52483
Showing that $(m)\cap (n)=(\operatorname{lcm}(m,n))$ and $(m)+(n)=(\gcd(m,n))$ for any $m,n\in\mathbb{Z}$
15452
Proving determinant product rule combinatorially
42141
Proving Distributivity of Matrix Multiplication
45460
Proof verification of a number theory problem involving sequences.
43310
Proving $A\cap(B-C)$ is equal to $(A\cap B)-(A\cap C)$
139350
Given two coprime integers, find multiples of them that differ by 1
24212
proving how many permutations exist.
78188
How can I get the smallest possible answer with the Chinese Remainder Theorem?
74809
GCD to LCM of multiple numbers
27610
Given the permutation $\sigma=\left(\begin{array}{ccccc} 1&2&3&4&5\\ 3&1&2&5&4 \end{array}\right)$
44076
Proving if $d_0$ is the smallest positive integer in $S$ then $d_0 = \gcd(a,b)$