When your faster students have finished their classwork, give them an extra challenge with one of these reusable write-on/wipe-off activity mats. Aligned with the Common Core, these math activities will ensure you are differentiating for the fast workers in your classroom. Students check their own work with a fun-to-use decoder, then wipe the card clean so that it's ready for the next student to practice decimal comparisons, rounding, adding and subtracting fractions, multiplying fractions, multidigit multiplication, and division skills.