When I was a kid my teachers would mock me for getting things wrong, make me stand infront of the whole class and try to resolve problems and they'd laugh at me if I failed.

I've always liked math, but in environment such as school I get very anxious and can't perform to the best of my ability.

How do I control this? How do I stop being paralyzed when I have to do math infront of other people? How do I stop being worried of being called to demonstrate something so I can actually pay attention to the lecture?