What is the approach for solving these kinds of modular arithmetic?
360
Modular exponentiation by hand ($a^b\bmod c$)
77024
Find the number of solutions of $x^2=x\mod m$ for any integer $m$
102204
Factoring product of two primes from solutions of congruence
36713
Solving multiple congruences by CRT = Chinese Remainder Theorem
9118
Polynomial division: an obvious trick? [reducing mod $\textit{simpler}$ multiples]
58803
${n \choose k} \bmod m$ using Chinese remainder theorem?
36438
How to solve infinite repeating exponents
43683
Finding Inverse of 2 (mod m)
99815
Dividing versus multiplying by inverse in modular arithmetic
133925
Find All Solutions to System of Congruence
93094
How do I solve this problem on maximizing sum modulo a given number?
114011
Algebra - Solving for three unknowns.
73079
Eliminating non-integer solutions to $ab / (2\sqrt{ab} + a + b)$
74898
$1^n +2^n + \cdots +(p-1)^n \mod p =$?
89705
How to solve $a_n = 2a_{n-1} + 1, a_0 = 0, a_1 = 1$?
45882
Solving a congruence without Fermat's little theorem
119433
How to find modulo of large numbers like $9801\! \pmod {\!32}$