Game guide:Making a child or younger live alone
How to do
(Note:This only works on The Sims 3.)
There are two ways of making a child or younger live alone. The first way consists of killing off the parents, then play the child again straight after it gets you off the household. Notice the babysitter will stay no matter what. The second way consists of playing another household and make the parent of the desired household with the child the player wants to live alone. Make the parents join the household through "testingcheatsenabled true", then go on to the newly alone child.