I'm glad you had a positive experience. As your son is experiencing, a negative one can be so harmful. I had the same maths teacher from Years 8 - 11 and aside from consistently using me as an example of what not to do and recommending I left school at 16 without continuing my education, she told me (and the class) I was 'thick' on more than one occasion. Learning difficulties and disabilities weren't noted in the same way then. All you're left with is a lifetime of feeling stupid.

I echo this. I had two inspirational maths teachers who gave me my love of maths But this was ultimately caused by my chemistry teacher, an old guy who had taught my clever brother 8 years earlier. Handing out the end of term exam marks where I came top he said, “Holmes: 96. Your brother got 98” I never forgave or forgot that remark and vowed, “Right, you bastard, I’m not going to go through life being compared with my brother, I’m doing maths” And so I did. Even did a maths degree.

Always struggled with maths until I was taught by Mrs Garner. Brilliant teacher who helped me scrape a GCE

I had a very similar experience at school with my maths teacher. Belittled me in front of the class. Both my parents were maths teachers and knew the syllabus better than him. They met with the school and he never taught my year in sixth form despite being head of maths.