There are six fractions of shares mentioned in the Quran:
2/3, 1/2, 1/4, 1/8, 1/3, 1/6.The 2/3 share is for two or more daughters; for two or more son’s daughters; for two or more sisters; for two or more half- sister;
The 1/3 share is for two or more of mother’s children; for the mother in the absence of child, or son’s child or two or more brothers or sisters; some times for the grand father when there are brothers and sisters, The 1/2 share is for one of the four sets of females mentioned above when she is alone. for the husband when his wife leaves no issue.
The 1/4 share is for the husband when the wife leaves children; for the wife when the husband leaves no children The 1/8 share is for the wife when her husband leaves children
The 1/6 share is for the father when the deceased leaves children; for the grandfather; for the mother when the deceased leaves children or two or more brothers and sisters; for the grandmother when the deceased leaves children or two or more brothers and sisters; for the son’s daughter when the deceased has one daughter; for one or more half – sisters when there is a sister for two or mother’s children; When a father and spouse are alive, after assigning the respective shares due to them, One Third of the Remainder will be assigned to the mother. The portion assigned to the wife has to be shared equally by two or three of four wives.