Chinese Remainder theorem (along with other results).
First note 92= 4 × 23 with gcd(4,23) =1.
Let us call N= 1992.
We will compute, N(mod 4) and N (mod 23) and then use CRT tocompute N (mod 92).
First, N (mod 4) = (19)92( ð‘šð‘œð‘‘ 4) = (−1)92(ð‘šð‘œð‘‘ 4) = 1and ð‘(ð‘šð‘œð‘‘ 23) = 194.[(19)22 (ð‘šð‘œð‘‘ 23)]2(ð‘šð‘œð‘‘ 23) = (−4)4(ð‘šð‘œð‘‘ 23) = (16)4(ð‘šð‘œð‘‘ 23) = (−7)2(ð‘šð‘œð‘‘ 23) = 49(ð‘šð‘œð‘‘ 23) = 3.
Note in the above we have used Fermat’s Little Theorem.
Now, If you know CRT,
you candirectly say ð‘( ð‘šð‘œð‘‘ 92) = 49.
If not, you can compute it.