Great center for your kids to practice solving addition and subtraction problems with visual aids AND to get them used to showing their work in Math.
Print, laminate, and cut into fours.
Stick in a folder with a white board marker and an eraser.
This center can be mixed together into one folder or separated into addition or subtraction piles.
Once your kids get used to doing this you can be sure they will be able to demonstrate how they got to their answer AND become confident in checking their own work to make sure they are correct.