How is inheritance divided among the the father, mother, son, and daughter?

If the heirs are limited to the father, mother, son, and daughter, then the father and mother each receive one-sixth due to the existence of offspring. The remainder is divided between the son and daughter, with the male receiving the equivalent of the share of two females. Thus, the inheritance is divided into 18 shares: 3 for the father, 3 for the mother, 8 for the son, and 4 for the daughter. It is important to note the necessity of referring inheritance matters to Sharia courts to verify the existence of other heirs, or wills, or debts that take precedence over the rights of the heirs.