How to reflect an angle

This may be more of a math question, think of how the ball ricochets off the walls and paddles in pong or brick breaker, I can see that the new angle is equal to the angle that it came in at, but when you have to do it in a unit circle, I can’t figure out how to mathematically figure it out. Can someone explain how? TY for any help!

normal + (normal - angle)

-2*(V dot N)*N + V

Here’s the article I wrote about it in a qbasic emag:

www.petesqbsite.com/sections/express/issue21/index.html#bounce