If it's only, or mainly, homework that's the issue right now, could you act as a buffer for a bit? Let her complete the homework, then you check it before it goes back to school and have her correct any mistakes?

Honestly, scoring 10% sounds more like guessing than like making careless errors, and I might be more inclined to see it as non-compliance than as a work technique issue - but it depends on a lot else so I just throw the thought in for you to see if it chimes.

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