Bismillah Walhamdulillah Was Salaatu Was Salaam ‘ala Rasulillah Narrated Ibn ‘Abbas (Radi-Allahu ‘anhu):
The
custom (in old days) was that the property of the deceased would be
inherited by his offspring; as for the parents (of the deceased), they
would inherit by the will of the deceased. Then Allah cancelled from
that custom whatever He wished and fixed for the male double the amount
inherited by the female, and for each parent a sixth (of the whole
legacy) and for the wife an eighth or a fourth and for the husband a
half or a fourth.
Bukhari Vol. 4 : No. 10