  Let $f(x)$ be an irreducible polynomial with integer coefficients of degree
at least two. Hooley proved that the roots of the congruence equation
$f(x)\equiv 0\mod n$ is uniformly distributed. as a parallel of Hooley's
theorem under ideal theoretical setting, we prove the uniformity of the
distribution of residues of an algebraic number modulo degree one ideals. Then
using this result we show that the roots of a system of polynomial congruences
are uniformly distributed. Finally, the distribution of digits of n-adic
expansions of an algebraic number is discussed.
