Using Fermat's little theorem to find remainders.
77351
How to use Fermat's little theorem to find $50^{50}\pmod{13}$?
134159
Smallest value of $a^2 + b^2 + c^2+ d^2$, given values for $(a+b)(c+d)$, $(a+c)(b+d)$, and $(a+d)(b+c)$
22029
Solving modular arithmetic questions
139776
Divisibility tests and remainder mod $9,11,99,101,999,1001\,$ (casting out nines and elevens)
110460
find remainder of a number
45460
Proof verification of a number theory problem involving sequences.
82913
Is this a proof of Fermat's Last Theorem where n = 3?
99086
Continued fractions
19459
Find remainder of $F_n$ when divided by $5$
93820
Fermat's little theorem applied for $n$'th root existence $\!\bmod p$
58803
${n \choose k} \bmod m$ using Chinese remainder theorem?
117743
Remainder of the polynomial
52856
Taylor's Theorem with Peano's Form of Remainder
74523
Proof by Cases involving divisibility
16697
Fermat Last Theorem for non Integer Exponents
100720
Negative quotients and their remainders
134450
Chinese Remainder Theorem $\ x\equiv m_k-2\pmod{m_k}$