Both DS9 and DD7 are perfectionists, although in different ways for different subjects. For math, what sometimes works for DS is I will work through a math problem from the book, but purposely get a wrong answer.
Let's see, what is 1/2 plus 3/4? 1 plus 3 is 4, and 2 plus 4 is 6, so the answer must be 4/6!
I then let him correct me, and we laugh about it. Sometimes I pretend to be Joe (a not-so-bright character from Life of Fred). If I get the correct answer, I'll get free pizza for life, or some such silliness. The goal is to let him see that making a mistake isn't the end of the world, and model gracefully recovering from a mistake by brushing it off, figuring out the right answer, and moving on.
