Students get to play to become a teacher!
I love this resource for the students, usually I would thell them is their turn to correct some exercises.
The idea is they have to look carefully at each addition, some of them are correct and some are not.
If the addition fact is correct they have to circle with red the sum and if it's incorrect they have to cross with blue the sum.

Disclaimer: I downloaded this resource from superteacherworksheets with a paid account.