This unique, write on wipe off time tool allows students to measure and teachers to demonstrate time in a number line format where they can visually see where the time goes! Elapsed time and duration of time subjects are difficult for students to grasp and digital clocks only make it harder as students are failing to adequately learn to tell time using analog clocks. The Elapsed Time Ruler™ was created to address this difficulty and help teachers instruct students on elapsed time and duration of time questions. The student version of the Elapsed Time Ruler™ is designed to interlock at each side marked "midnight" to create one continuous time line. Student version is laminated on the front to allow the use of dry erase markers to mark the beginning and ending times if needed. Details: YellowSet of 1224-hour format A.M. marked in red and P.M. marked in blueRecommended for ages 7 to 11 years old