She’s lazy. Not everything is ADHD

My 9 year old child does this but he doesn't have ADHD and he isn't supremely gifted. He just refuses to double check his work.

My 8th grade DD was and is the same. I believe that while she may have inattentive ADHD, another issue is simply lack of practice in late elementary. Her teachers rarely sent home math homework to practice some pretty critical skills. I think the idea of doing some drill at home is good. Also just discussing how to check your work.

Does she find the work reasonably interesting and challenging, or flat out boring? Boredom causes inattention and sloppiness.