My uncle says that a billion is a million million. Is he right?
Well, he is and he isn’t! There are two meanings for the word ‘billion’. The ‘long scale’ meaning of one million million, or 1 000 000 000 000, is the one your uncle probably learned at school and this was the version in use in the UK until 1974. Unfortunately this meaning of billion defined a number too large to be of much practical use and the definition was altered in 1974 to the so-called ‘short scale’ version with a value of one thousand million (1 000 000 000), thereby bringing its definition into line with the rest of the world.
