Muwatta Imam Malik (Riwayat Yahya)

Imam Malik, may Allah have mercy on him, said that if the grandfather and his brothers and sisters are present along with any of the possessors of fixed shares (dhawi al-furud), then first the possessors of fixed shares will be given their prescribed shares. After that, whatever remains, one of several options will be chosen for the grandfather, whichever is better for him. These options are: one is that the grandfather is given one third of whatever wealth remains. The second is that the grandfather is considered as one of the brothers, and he receives the same share as one brother. The third is that he is given one sixth of the total wealth. Whichever of these options is better for him, that will be done. After giving the grandfather his share, whatever wealth remains will be divided among the brothers and sisters as «﴿لِلذَّكَرِ مِثْلُ حَظِّ الْأُنثَيَيْنِ﴾», except in one case where the division will be done differently (this is called the Mas’alah Akdariyyah). That is: if a woman dies and leaves behind a husband, mother, full sister, and grandfather, then the husband will get half, the mother one third, the grandfather one sixth, and the full sister half. Then the grandfather’s one sixth and the sister’s half will be combined and divided into three parts: two parts will go to the grandfather and one part to the sister.