Process of elimination

There are three occupants who live under my roof; me, the wife, and the baby. Of these three, only two have full control of their arms and legs and only two have a highly developed thought structure. I get a call at working asking if I ate the last piece of cake? "Please tell me you've figued the math out." I gotta wonder if somewhere I miscounted. Is there a fourth occupant that would justify this call or is someone giving the baby way too much credit.?