Tradition specifies ten as the least number; but the matter was probably left altogether to the discretion of the heads of families.
The last clause should be rendered: “each man, according to his eating, ye shall count for the lamb.”
Related Commentaries of Exodus 12:4
Exodus 12:4
4 And if the household be too little for the lamb, let him and his neighbour next unto his house take it according to the number of the souls; every man according to his eating shall make your count for the lamb.