Solving $9x \equiv 21 \bmod 30$
978
Solving $ax \equiv c \pmod b$ efficiently when $a,b$ are not coprime
109490
Modular arithmetic problem (mod $13$)
140143
Find $n$ satisfying the equation $[\log_21]+[\log_22]+[\log_23]+\dots[\log_2n]=1538 $
15897
Solve a congruence $1978^{20}\equiv x\pmod{125}$
119146
How to solve $n < 2^{n/8}$ for $n$?
121122
Calculate $2^{5104} \bmod 10$ using mental arithmetic
51153
Number of solutions to $x^2\equiv a\pmod m$
131941
Solve quadratic congruences.
21530
How many solutions of $\mod 63$ : $x^2=1 \pmod7 $ and $x^3=1\pmod 9$
26301
Prove that $x^3 \equiv x \bmod 6$ for all integers $x$
118955
Specific steps in applying the Chinese Remainder Theorem to solve modular problem splitting modulus
77024
Find the number of solutions of $x^2=x\mod m$ for any integer $m$
73020
Every integer is congruent to the sum of its digits mod 9
131395
Solving linear congruence $2x + 11 \equiv 7 \pmod 3$
81058
Evaluate $6^{433} \pmod {21}$ and a proving question
144802
Prove no solution to $x^2\equiv3\bmod5$
145617
Is there any simple trick to solve the congruence $a^{24}\equiv6a+2\pmod{13}$?