Nice job of pointing out the child’s very obvious shortcomings in writing and math.
It seems to me that many of these sort of children have very little skills in the way of writing and math.
I would bet she is polite as can be! Greets people in a very proper tone and the whole nine yards!
The mother is neglecting her and milking the system. She has allowed her daughter to fall so far behind, it will require herculean effort to catch up.
But, you are right, she is probably just as polite as they come
Being illiterate and innumerate engenders politeness? Not based on the sample around here.