When I was about 10 years old, I had an imaginary friend. His name was Eleven while my (nick)name was Nineteen (my favorite number back then). We often made bets like "I bet [insert name] will be at school today". When it was true, I scored, but when it was false, Eleven scored instead. I think I was even keeping track of our scores.
Later, we (me and Eleven) found two more friends: Fifteen, and Ten.Fifteen scored when the bet was half true and half false (since 15 is half-way between 11 and 19).Ten scored when the bet was neither true or false or completely unclear.
A childhood belief about imaginary friends

others believed things like this
- I used to believe that a hat trick in football was achieved when a player scored a goal with their head!— Andy
- I used to believe that your belly button was what held your top half to your bottom half...— Debelouwho
- When I was nine, I thought two eleven-year-olds could get married.Anon
- When I was very young, I assumed that false teeth were taken from dead people's teethAnon
- when I was 6 years old i use to believe a catfish was half cat one fish.Anon
- I am Canadian and when I was little I would sing "True Pastry Love" instead of 'True Patriot Love"— Jess