Chinese remainder theorem where some modulo are not coprime
325
If every pair of congruence equations admits solutions, then the entire system admits solutions
50047
How do I use the Chinese remainder theorem to find all the square roots of 11 in $\mathbb Z_{35}$?
41295
Divisibility, LCM and GCD for fractions (rationals)
28644
For $q, p$ odd primes such that $p \neq q$, there is not primitive root modulo $pq$.
978
Solving $ax \equiv c \pmod b$ efficiently when $a,b$ are not coprime
48480
Find two elements that don't have a gcd in a subring of Gaussian integers
16697
Fermat Last Theorem for non Integer Exponents
55621
Show that if $c_1, c_2, \ldots, c_{\phi(m)}$ is a reduced residue system modulo m, $m \neq 2$ then $c_1 + \cdots+ c_{\phi(m)} \equiv 0 \pmod{m}$
42754
Modular arithmetic: division, fractions, solving linear congruences
15897
Solve a congruence $1978^{20}\equiv x\pmod{125}$
20161
Prove that the multiplicative inverse of $a$ modulo $m$ exists if and only if $a$ and $m$ are coprime.
39969
Algorithms for computing multiplicative order modulo $n$
99037
Prove the sum of all numbers that do not have a multiplicative inverse mod $n$
109490
Modular arithmetic problem (mod $13$)
38911
Squares in $\mathbb{Z}_p$ that are not squares in $\mathbb{Z}$
139350
Given two coprime integers, find multiples of them that differ by 1
134450
Chinese Remainder Theorem $\ x\equiv m_k-2\pmod{m_k}$