This is a great way to practice finding the C.R.O.C. that allows for demonstrating mastery and incorporates problem solving. The students use the digits 0-9 to fill in the blank spaces. When they arrive at the last question they must decide which number placements make the statement true. It can prove to be challenging but enjoyable. My students enjoyed using a dry erase marker on plastic sleeves instead of number tiles. This appeals especially to those students that are hands on learners.