Be very wary of ADHD diagnosis, The consequences are huge and have a massive impact on childrens lives.
I hate all ADHD diagnoses, for me I have always seen just naughty children who need time to develop at their own pace and not develop at someone else's pace or for the benefit of any school cariculum or parental needs.
Do not give any child medication to control ADHD, why would you give an amphetamine to any child
I have had this a few times working with children and I have always suggested looking into Dyslexia.
you say "he is good at math but would often misread the problems and answer the wrong question".
This for me is Dyslexia.
how can a child concentrate when he cannot understand what is in the books he is supposed to be able to read.
The child inevitably becomes disruptive so they are not shamed by adults or their peers for being stupid.
call a psychologist and have a Dyslexia test