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 is His slave and Messenger.
First of all, it should be noted that each one of you must fear Allaah and not open the door for the devil to disunite you and lead you to sever your ties of kinship. Moreover, you should rule by the Book of Allaah and the Sunnah of the Prophet acting in compliance with the Saying of Allaah (which means): {And if you disagree over anything, refer it to Allaah and the Messenger, if you should believe in Allaah and the Last Day. That is the best [way] and best in result.}[Quran 4:59]. If the matter is as you mentioned in the question that your father died and left a wife, three sons and four daughters and did not leave any other heir, then the wife is entitled for an eighth-portion of the inheritance, and the remaining should be divided amongst the children, the male twice the portion of the female.
Therefore, the inheritance should be divided into 80 shares, the wife will get 10 shares, each son will get 14 shares, and each daughter will get 7 shares. Then, the children will divide amongst them the inheritance of their mother (i.e. the 10 shares); the male twice the portion of the female. This means that each son will get 2 shares from the inheritance of his mother and each daughter will get 1 share. This is of course if she did not leave any other heir. This is the principle in dividing the inheritance of the father and the mother .
As regards the issue of marrying off some of the daughters, then it is not permissible for you to deduct anything from the share of the daughter who was married off by her father while he was alive just because she was married off. However, the one who was married off by her mother is different, if the mother married her off with her own money [mother's money], then the brothers have no right to deduct her share in the inheritance and they have no right to force her to renounce her share in the inheritance. The daughters who renounced their right due to being forced to do so (or were never consulted), are permitted to ask for their rights later, but whoever renounced her right with her own will and consent, then she has no right to ask for her share if those to whom she renounced her share had possessed what she renounced to them, as it is not permissible to take back a gift. However, if she renounced her right and then asked for it before they had possessed it, in this case it is permissible for her to take back her gift because the gift can only be taken back if the recipient never possessed it.
Nonetheless, if the mother had spent from the inheritance in marrying off her daughters, then the sons have the right to deduct this amount from their share of inheritance without being unjust to them.
With regard to the eldest sister who got married while her father was alive, then the expenses of her marriage should not be deducted from her share in the inheritance of her father as already mentioned, and she has the right in her full share of inheritance unless she renounces her right with her full consent without her being cheated or deceived.