How is inheritance calculated with a father, a paternal grandfather, a mother, a maternal grandmother, and a paternal grandmother among the heirs of the deceased?

If the deceased leaves behind only the parents, the mother receives one-third as a prescribed share, and the father receives the remainder by way of ta'sib (residuary inheritance). The two grandmothers receive nothing because they are excluded by the mother, and the grandfather receives nothing because he is excluded by the father. The estate is divided into three shares: one share for the mother and two shares for the father. Matters of inheritance must be referred to the Sharia (definition) courts to verify the existence of other heirs, bequests, or debts.