Hi Ren,
Welcome to new math. That's just how they do it. Sit down with the teacher, and politely ask what are the acceptable answers and then hothouse your DD.
Whose attitude seems like it needs adjusting? Yours? Your daughters? Your Teachers?
I don't think your daughter will be faulted for using negative numbers - it's a possiblity, but better to test the waters and find out than assume it's not allowed.
You can also call up the text book company and ask them to get someone on the phone and explain it to you.
It is, for example, ok to say, in some rooms, 'I consulted a table of math facts' or 'I counted buttons.' It does make my skin crawl, but is this really the hill you want to die on? In the long run I think this is just one of those unavoidable fads.
((hugs))
Grinity
