This is a great way for your students to practice the midpoint point formula. There are basic midpoint point problems, 3-D midpoint problems, and midpoint problems that they have to find the end point.
Before cutting it out, put a letter on the left of each card (not in alpha order). This will make it easy for you check if students put it in the right order. I was unable to do it for you because it messes up problems and answers. When it is time to cut it out, DO not cut on the dotted lines!
If you haven't played dominos before in your class, have the students find the start and do the problem that is attached to that domino. Once they have finished that, they find their solution (which is in on the left of the dominos) and place it next to the problem. Then they do the problem to the right of the answer. If you haven't played before, I suggest you trying it out before giving it to the kids.
I hope you enjoy it!