Sefer Ha’mitzvos Ha’Katzar (The concise book of mitzvos)
By the Chofetz Chaim
This book lists the Torah mitzvos that can be observed today
First Section – the Positive Commandments
73. It is a positive commandment to judge judgments about inheritances
As it states in Bamidbar (Numbers) 27:8, "A man that dies and he has no son, his inheritance goes to his daughter." A son comes before a daughter and all of a person's male children come before a daughter. A daughter and all male children come before the deceased person's father. Included in this commandment is that the firstborn son gets a double share of the inheritance. A husband inherits from his wife according to the Law of the Sages and he is before all others that inherit.
This applies in all places and at all times.