I woke up early one morning with this idea swirling around my head and I just had to get it out and on paper. I began to work it thru and then used it on my own students and it worked over and over and over.
Print the number of sheets you need for each class then cut them into strips. Hand a "worm" to each student as they enter your classroom.
First, select the first initial of the first/last name of the seventh/eighth student who walks in your room for each class. Give each student that letter to fill out their "worm". Allow them 5 minutes to complete the assignment then have them exchange with the student next to them – forward/backward/sideways etc.
Give that student a couple of minutes to check the answers and circle the correct ones the write the correct number at the bottom and initial the score. Then, have them pass the worms up and give points as you so desire and the "Kick the can on down the road" or as far as the next time you use this bell-ringer.