Questions on divisibility, gcd and lcm, congruences, linear Diophantine equations, Fermat's and Wilson's theorems, the Chinese Remainder theorem, primitive roots, quadratic congruences, quadratic number fields and other related topics which may be treated in first courses on number theory. More advanced topics should instead use the number-theory or other tags.

Questions on introductory topics: divisibility, gcd and lcm, congruences, linear Diophantine equations, Fermat's and Wilson's theorems, the Chinese Remainder theorem, primitive roots, quadratic congruences, quadratic number fields, Pell's equations and other related topics which may be treated in first courses on number theory.

For more advanced topics, please use pertinent tags, e.g. , , , or tags.