Assalaamu alaykum. Please calculate the inheritance according to the following information: - Does the deceased have male relatives who are entitled to inherit: (A son) Number 3 - Does the deceased have female relatives who are entitled to inherit: (A daughter) Number 1 - Additional information: We are three sons and one daughter of our deceased father. Our father has left us one apartment and a shop. All of the three sons agreed to give the only daughter the same share as them as their wish without being forced. Is it halal for the daughter to accept this?

All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger. 

If the deceased did not leave any other heirs entitled to inherit except those mentioned in the question, then the estate should be divided among the deceased's sons and daughter by virtue of taʻseeb (i.e. by virtue of having a paternal relation with the deceased and not having an allotted share, so they get what is left after the allotted shares have been distributed). Allaah, The Exalted, says (what means): {Allaah instructs you concerning your children: for the male, what is equal to the share of two females...} [Quran 4:11]

Hence, the estate should be divided into seven shares; each son gets two shares, and the daughter gets one share.

It is permissible for the three sons to give their sister the same share as the share of a son or even more. It is halaal (lawful) for her to accept this willful grant from her brothers provided that each of the brothers is eligible to make this grant, meaning that each brother is sane, adult, and has a mature intellect.

Allaah knows best.