This self checking, NO PREP math activity is perfect for Earth Day! This product contains an addition mystery picture with 9 2 digit addition problems, a student "show your work" page, and answer key. This is the perfect addition to supplement your math instruction, use a math center, or for students who need a little extra math.When students type in their answer, the product will:Turn green if correct, and reveal part of the mystery pictureTurn red if incorrect, signaling to try the problem aga