It has always driven me crazy to hear otherwise intelligent people say “I’m no good at math.”
The idea that the ability to understand or do mathematics is a yes-or-no attribute that cannot be altered is absurd but it’s widespread. I think some people embrace the idea because it (a) is an acceptable excuse for not trying, and (b) they think it indirectly says “which means I’m very creative and artistic”. @#%^$&#$!!!!
The reality, of course, is that like any other skill, mathematical ability is partly a function of in-born talent but mostly a function of effort and desire. Nobody can or will put effort into something if they think it can’t change, which is why it is increasingly obvious that the most important factor in whether a kid learns math is whether the kid thinks it is possible for him or her to learn math. One a kid think “I’m no good at math” then it’s story over.
This story at Quartz talks about research in the field.