The first scene has 2 daughters and 1 son then we never hear of the 2nd daughter ever again. Of course some have said the 3rd child isn't a daughter but rather a neighborhood child the mother paid to help with laundry or was baby sitting for someone else since they never directly call the child out as being a child of the family. She is just helping the mom with the laundry and is then never seen again.
Wow I've seen this many times and haven't noticed lol. Next time I will be paying closer attention!