I do know Dyscalculia is a thing but I think the not being good at maths is wider than that.
www.bdadyslexia.org.uk/dyslexic/dyscalculia
Dyscalculia is usually perceived of as a specific learning difficulty for mathematics, or, more appropriately, arithmetic.
Developmental Dyscalculia often occurs in association with other developmental disorders such as dyslexia or ADHD/ADD. Co-occurrence of learning disorders appears to be the rule rather than the exception. Co-occurrence is generally assumed to be a consequence of risk factors that are shared between disorders, for example, working memory.
My working memory as a child was very poor my mental arithmetic was very poor indeed - but give me a pen and paper I could do maths. ( I was still using fingers and working out some of the times tables I couldn't remember form ones I could in secondary school got a maths A-level though)
I come from a family full of good mathematicians including female one so got help and support with maths. It's also why we did something rather than accept being told your DC just aren't good at maths.
I'm dyslexic - I love reading - I struggled pronouncing unknown words I'm not always accurate in what I read and I really struggle with spellings - but I love reading books. No one ever said to me - oh reading isn't a strength don't bother with it.