How did he turn around his education from being the "dumbest" to being the smartest in the 7th grade

In 7th grade, Carson passed his math class. True, he passed with a D, but he'd had an F and raised his grade. Suddenly, he saw himself as improving, and he stopped seeing himself as a failure.

"Seeing that passing grade made me feel good. I thought, I made a D in math. I'm improving. There's hope for me. I'm not the dumbest kid in the school."