Then, after grandparents died, 50% of what they owned was distributed as inheritance, which was evenly distributed according to the number of grandparents' children (three children in your family and four in Wang Fa * * *), and the share of the eldest son was subrogation inheritance.
That is to say, you have 25% first, then 50% of 25% (12.5%) comes from subrogation inheritance, and 32.5% comes from * * *.