My DD12 does the same thing.... Not only in math but even when following a recipe she'll skip through the directions and just do it. I think sometimes it is the result of being bored in school and having to do the same thing over and over that she assumes she knows. In math most of her mistakes are careless errors. I have gotten on her case alot about it. It becomes really important when it influences the future of thier schooling. That said we have been recommended to see a vision therapist to see if she is having troubles in that way. If there is trouble that way I will be sorry for the harrassment for something that was not her fault...or easily under her control... One thing I did that actually did help was use money... I know its not the best thing to do but I really wanted to show her that she could do the work and get them right and I knew the money would motivate her. This was a little less than two years ago and a prealgebra class. I think I offered to pay her $25 for the whole lesson if nothing was wrong. It took two lessons or so and she got them all right which proved to herself that she could do it.
