This is a frequently referred to surah in An-nisa:“…..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”If allah is completely just, why does a female get less inherience

According to Islamic Shariya girl inherits from her father property and boys too. When this girl marries and becomes a wife then in case of her husband’s death she inherits from her Husband too but what about a boy who can inherit from his father but the property his wife has from her father in that he has no share unless his wife gives him from her own wish.
Now please refer this verdict no 2740 and 2742 from the Islamic laws of Ayatullah Sistani.
So it’s not unfair if you calculate properly the shares of a girls.But because the society where do we live normally girls are ignored from their share but it is not an Islamic Shariya.