The word(s) "sixth" appears 5 time(s) in 4 verse(s) in Quran in Saheeh International translation.

(1) Allah instructs you concerning your children: for the male, what is equal to the share of two females. But if there are [only] daughters, two or more, for them is two thirds of one's estate. And if there is only one, for her is half. And for one's parents, to each one of them is a sixth of his estate if he left children. But if he had no children and the parents [alone] inherit from him, then for his mother is one third. And if he had brothers [or sisters], for his mother is a sixth, after any bequest he [may have] made or debt. Your parents or your children - you know not which of them are nearest to you in benefit. [These shares are] an obligation [imposed] by Allah. Indeed, Allah is ever Knowing and Wise.

(2) And for you is half of what your wives leave if they have no child. But if they have a child, for you is one fourth of what they leave, after any bequest they [may have] made or debt. And for the wives is one fourth if you leave no child. But if you leave a child, then for them is an eighth of what you leave, after any bequest you [may have] made or debt. And if a man or woman leaves neither ascendants nor descendants but has a brother or a sister, then for each one of them is a sixth. But if they are more than two, they share a third, after any bequest which was made or debt, as long as there is no detriment [caused]. [This is] an ordinance from Allah, and Allah is Knowing and Forbearing.

(3) They will say there were three, the fourth of them being their dog; and they will say there were five, the sixth of them being their dog - guessing at the unseen; and they will say there were seven, and the eighth of them was their dog. Say, [O Muhammad], "My Lord is most knowing of their number. None knows them except a few. So do not argue about them except with an obvious argument and do not inquire about them among [the speculators] from anyone."

(4) Have you not considered that Allah knows what is in the heavens and what is on the earth? There is in no private conversation three but that He is the fourth of them, nor are there five but that He is the sixth of them - and no less than that and no more except that He is with them [in knowledge] wherever they are. Then He will inform them of what they did, on the Day of Resurrection. Indeed Allah is, of all things, Knowing.