I once thought that the octane numbers on gas tanks were the years they had been manufactured in (ex: 87 octane was actually '87 octane), and that 93 octane (called Ultra 93) had just come out that year.
A childhood belief about cars

others believed things like this
- I used to believe that electricity was manufactured in a factory in a place called 'Electriz City'.— Sally
- I used to believe that numbers had gender, that the odd numbers were boys and even numbers were girls. — Evelyn
- I used to believe there were numbers called "onety" and 'twoty." I thought "twoty-nine" came before twenty.— CC
- I similarly thought that "Proud Mary" included the lyrics "pumped a lot of tanks down in New Orleans."— Larry
- I used to be terrified of the numbers 18 and 19. I think I thought that when you turned 18 or 19, you die.— Emmy
- German tiger tanks shot out tigers, the invading army would get mauled to death by all the tigers— Bob