Albert Barnes Commentary Exodus 12:4

"and if the household be too little for a lamb, then shall he and his neighbor next unto his house take one according to the number of the souls; according to every man`s eating ye shall make your count for the lamb." — Exodus 12:4 (ASV)

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, you shall count for the lamb.