No interest as in she cannot concentrate on school work and it is frustrating for her so she avoids it....no interest as in she is bored by it because she already knows most of it...no interest because she is interested in other things??
Maybe it is the school?
Or, worst case maybe she has ADD.
We need more information in order to answer this question.
Google exactly what you typed....there is a lot of helpful advice and instruction out there...on internet. Let me know how you make out
Marie75