Mr. Smith has 4 daughters. Each of his daughters has a brother.
How many children does Mr. Smith have?
He has 5 children, all of the daughters have the same 1 brother.
Why this works
This riddle plays with the assumption that each daughter might have a different brother. However, the key lies in the wording: "each of his daughters has a brother" implies they all share the same single brother. So, with Mr. Smith having 4 daughters and 1 brother, he has a total of 5 children. It's a clever way to challenge our assumptions about family structure!