Geared clock teaches elapsed time using number lines. Help children calculate in tervals of time and solve elapsed time problems. Advanced NumberLine Clock comes with a clock frame and 2 detachable number line chains—1 for AM and 1 for PM. Simply unfold the number line chains, snap them together, and you’ve created a number line out of a clock. The Advanced NumberLine Clock also includes 3 different styles of analog clock designs, allowing children to practice telling time on clock styles they might encounter in the real world.