Translation:

176. They ask thee for a legal decision. Say: Allah directs (thus) about those who leave no descendants or ascendants as heirs. If it is a man that dies leaving a sister but no child she shall have half the inheritance: if (such a deceased was) a woman who left no child her brother takes her inheritance: if there are two sisters they shall have two-thirds of the inheritance (between them): if there are brothers and sisters (they share) the male having twice the share of the female. Thus doth Allah make clear to you (His law) lest ye err. And Allah hath knowledge of all things.

Notes (Tafseer)

681. This verse supplements the rule of inheritance of the estate of a deceased person who has left as heir neither a descendant nor an ascendant. We shall call such a person A, who may be either a male or a female. In iv. 12 (second half), A's case was considered where he had left uterine brothers or sisters. Here A's case is considered where he has left brothers and or sisters by the father's side, whether the mother was the same or not. "Brothers" and "sisters" in this verse must be construed to be such brothers and sisters. For the sake of clearness, I have expanded the terse language of the original in the translation. Let me explain it more concretely in this note. A, and "brother" and "sister" being strictly defined as above, we proceed to consider how A's inheritance would be divided. If A left a widow or widower, the widow's or widower's share would first be calculated as in the first half of iv. 12; if A left no spouse, this calculation would not be necessary. Then if A left a single "sister," she would have a half share, the remaining half (in so for as it, or a part of it, does not fall to a spouse, if any) going to remoter heirs: if a single "brother," he would have the whole (subject to the spouse's right if there is a spouse); if more than one "brother," they divide the whole (subject to etc.). If A left two or more "sisters," they get between them two-thirds, subject to the spouse's right, if any. If A left a "brother" and "sister," or "brothers" and "sisters," they divide on the basis that each "brother's" share is twice that of the "sister" (subject to, etc.). In all cases debts, funeral expenses, and legacies (to the amount allowed) have priority as in n. 522.