Before class, make a list of famous people who have a Twitter account and indicate the number of people who subscribe to their account.
Ask the children to guess the number of subscribers of these famous people.
If they are far from the number, give a starting figure (for example, 5,000,000) and ask them to stand on one side of the room if they think they have more subscribers and on the other side of the room if they think they have fewer subscribers.