I am pretty sure you are not crazy Cola. BTDT.
When DD was hating math and doing similar things....stuffing up the easy stuff but able to do complex algebra I read that it wasn't unheard of. As a basic point, the more challenging work is interesting and engages the brain. Easy stuff sometimes doesn't get processed because they don't have to focus on it and they make silly mistakes. DD still makes errors of calculation but knows how to do problems that make my head hurt.
Not showing their work crops up a lot....and I mean a LOT. I understand your math system has become even more demanding in this area and I know there are pros and cons, but sometimes our kids çannot articulate what they do. They don't lways follow the steps like they are expected to but leap straight to the answer. It's like asking us to think of our mother's maiden name. You can do it but I doubt you can tell me how you got to the answer...you just knew it.
Word problems are another area that can cause problems. I remember googling this when DD also had issues. It might be that he needs so concrete instruction on the steps needed. I will try googling it again or others may have references for you.
Ii might help to tell you that your problems are not unique or even desperately unusual in the gifted population. I say come to forum and ask all you want. There just aren't that many other places to go where you have support and information that you need.
Hang in there!
