My DD (7) is perfectly good at maths. But she's convinced herself she isn't - maybe because there are some particularly able boys in her class (and maybe because her little brother loves maths).
I was hoping someone had been through the same thing and had some tips for how to build her confidence back up. It's becoming a problem because she's becoming frightened to try questions, even ones within her capability, and certainly nothing where she might have to think for more than a couple of seconds...and anyway I think this is way too young to decide you are bad at maths!