Questions on divisibility, gcd and lcm, congruences, linear Diophantine equations, Fermat's and Wilson's theorems, the Chinese Remainder theorem, primitive roots, quadratic congruences, and other related topics in the early study of number theory. More advanced topics should receive the number-theory tag instead.

Questions on divisibility, greatest common divisor, congruences, linear Diophantine equations, Fermat's and Wilson's theorems, the Chinese Remainder theorem, and other related topics in the early study of number theory.

For more advanced questions, please use the , , , or tags, as appropriate.