Elapsed time, and all time concepts, are tricky. Why? For one, time is more abstract. There isn’t an
algorithm to turn to in a pinch. Even adding and subtracting time
presents problems when going over an hour span. Another reason might be
that students have limited clock experiences. I find that students will stand and walk to the door to view the digital clock in the hall rather than use the analog clock hanging in our room. Not many people wear watches anymore
with the advent of cell phone clocks. Finally, adults might be to
blame. How often do you tell your children, “Three minutes” only to have
five or ten go by before you realize it? It happens to me all the time in the classroom. No matter the reason, elapsed
time can be especially difficult to master. Here are two of my
favorite strategies for teaching elapsed time. The first is elapsed time using a number line. The second is elapsed time using a t-chart. I have found that most students prefer the number line method. Some do not need to make as many "hops" as shown in the video, but rather make larger "hops" of 10 to 15 minutes. I encourage the students to label ALL elapsed time problems with the words "start time", "end time" and "elapsed time" and to then analyze to see which they are solving for in the problem.