Hi folks! This may sound like a silly question, but I'm trying to clarify the notion of the Hebrew birthright (the fact that the firstborn gets a "double portion") by translating it into a picture using 100 dollars. But I'm usually bad with anything mathematical/involving numbers so I would like to know if I've understood it correctly.
Let's say a man has ten sons, of whom A is the oldest. The man has $100 at his death, so all things being equal, each son would normally receive $10.00.
BUT as A is the firstborn with the birthright, he gets a double portion (i.e. $20) while the other 9 brothers now share the remaining 80 dollars.
Is that how it works? If not, please use the "100-dollar" example above to get me straight on the concept... sigh. 
Thanks!