These centers were created to help reinforce how to use a ruler (centimeters and inches). There are 4 activities that have students measure different items and build a structure based on some measurment guidelines. There is also a cool ruler game that students could go to if they finish early. You could use it for a one day class period and have students rotate every 10 minutes or as learning stations set up in the back of your room during a measurment unit for students who finish early. Extensions could be made to challenge the students that need more. Happy Measuring.