In order to file as HH, you have to have a 'qualifying' person, ie a child, parent, or a qualifying relative other than your father/mother such as a grandparent, brother, or sister who meets certain other tests.

IF I remember my math correctly: There can be any one of four cars first (4) then there can only be three come in second x3 leaving two to come in second x2 then the loner x1 so 4x3x2x1= 24 possible combinations

You will have to wait until after January 15th (probably) after H&R offices open for the year. That's the problem with using a 'seasonal' office: They close after 4/15 and you don't' see them again until the next year!