My dd actually gets worse with practice.
Particularly timed practice?
DD7's math class is doing timed drills for addition / subtraction / multiplication (haven't covered division yet). She had 10 minutes for each sheet of 100 problems. She finished 50 or 60 multiplication problems, scattered at random around the page, as she picked out the ones she liked best. She finished 11 addition problems. On the subtraction page, she did no problems, choosing instead to write a diatribe about hating school and how annoying boys are.
I know she can subtract, because she never has any issues with the subtraction needed to solve a more difficult problem. And she doesn't get in trouble, because the teacher doesn't collect the timed practice sheets unless someone's finished and wants the reward for finishing. "I just fold it in half and stuff it in my desk when she calls time, and no one notices." LOL.
OP, I was the kid who made careless errors (and nearly failed math in 7th grade) because I didn't care about getting it right, and I did care about the ability to do it all in my head. Showing every step of the work really helped me when I decided I did care. I suspect that if she'd written out "6-2=5," rather than saying it, she might have caught the error.
