Elapsed Time Number-Line

We’ve recently been learning different ways to solve elapsed time problems.  One way that students found helpful was using a line so that it was easier to visualize the problem.  Marshall and Amanda created a video to help show one way to solve an elapsed time problem.

We found that using a number-line to solve elapsed time really helped a lot! We begin by drawing out a number-line. We place the beginning time on the left side and the ending time on the right. Then, starting on the left hand side, we find out what the next whole hour would be. We put how long it would take us to get from the beginning time to the next hour on our number-line. Then we jump to the ending time and we go backwards to the previous hour. In between that we put how much time is between those. Then, finally, we right down how much time is in between those two hours in the middle. We add up all of our time and we have the amount of time that has elapsed from the beginning until the end!

If you’d like your students to try out solving elapsed time with a number-line, feel free to use the worksheet below.

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51 Responses

  1. Alexus S. says:

    Dear Mr. Avery,

    I thought the video of Marshall and Amanda was amazing! My aunt and I watched it. I hope you have a great weekend!


    • Mr. Avery says:

      Dear Alexus,

      I’m really glad you and your aunt enjoyed the video! I think it’s amazing that we have a place where we can share all of our hard work with family and friends. I can’t wait for the class to create some more math videos!

      Mr. Avery

  2. Ariel D. says:

    Dear Mr. Avery,

    Amanda and Marshall did a great job. Yes the elapsed time video helped me a lot. Thank you for sharing it with us.


    • Mr. Avery says:

      Dear Ariel,

      I’m really glad that the elapsed time video helped you! I think Amanda and Marshall definitely did a wonderful job of showing us how to solve those problems. Hope you’re having a great weekend.

      Mr. Avery

  3. Mr. Salsich says:

    Dear Mr. Avery’s class,

    Thanks for that great video about how to solve elapsed time problems. This will be a big help to my third graders when we get into elapsed time next month. I have never tried this approach, but it is very similar to our number-line subtraction strategy so it will make a lot of sense to my class.

    Thanks for teaching a teacher!

    Mr. Salsich in Connecticut

    • Mr. Avery says:

      Dear Mr. Salsich,

      Thanks for your wonderful comment. We really enjoyed your number-line subtraction video and it helped us with our elapsed time problems! We’ll continue to check in with your blog so we can see all the great things your class does.

      Hope to hear from you again soon.

      Mr. Avery’s Class

  4. Mr. Miller says:

    Dear Mr. Avery’s Class,

    Well done Amanda and Marshall! This is a very informative and useful video. The two of you have an excellent understanding of elapsed time problems. :-)

    Mr. Miller

    • Mr. Avery says:

      Dear Mr. Miller,

      Thanks for your comment. Amanda and Marshall have definitely demonstrated an understanding of elapsed time. The whole class has done an amazing job with what can sometimes be a difficult concept.

      We will continue to check in with your blog throughout the year. Looking forward to speaking with you again.

      Your Friends,
      Mr. Avery’s Class

  5. Ben S. says:

    Dear Mr. Avery,

    I thought Amanda and Marshall did great! That really helped me in my math. How they explained it was amazing.

    Your Friend,
    Ben S.

  6. Miss T says:

    Dear Mr. Avery,

    It is our summer holidays and I thought I would pop in. How I enjoyed the video. It is a great way to solve such problems, so I did a bit of learning. We use such empty number lines for adding and subtracting so I was familiar with it, but I particulary enjoyed this video. Well done Amanda and Marshall.

    Miss T

  7. Trey says:

    Dear Mr. Avery,

    The video did help me with making number lines. I am starting to get it. Thanks Amanda and Marshall!


  8. Ben W. says:

    Dear Mr. Avery,

    Using the number line will really help me with my elapsed time problems. I will use it a lot in my life. Thanks Amanda and Marshall. :)

    Ben W.

  9. Mr. Avery says:

    Dear Class,

    I’m really glad that this video helped you with elapsed time. Marshall and Amanda did such a wonderful job of explaining it. I’m looking forward to all of you creating new math videos to help us understand other math concepts.

    Keep up the great work!

    Your Teacher,
    Mr. Avery

  10. Jenna K. says:

    Dear Mr. Avery,
    Amanda and Marshall did a wonderful job on the elapsed time problem. This elapsed time problem will help me in the future. I might need this elapsed time problem to figure out how to find how many hours passed in the amount of time in 7 days. The multiplication problem would be twenty-four times seven and that equals 168. I hope these elapsed time problems will help me. Keep up the good work.

  11. Kaylee W. says:

    Dear Mr. Avery,

    Amanda and Marshall did an amazing job! They should be in a movie. Before you illustrated the elapsed time number line, I was horrible! It really helped! :)

    Kaylee W.

  12. Marshall Smith says:

    Dear Mr. Avery,
    Do you think Amanda and I did a good job? Well, I hope you did because it was very hard to keep looking at the camera. I also think that introduction and ending thing was cool.


  13. Marshall Smith says:

    Dear Mr. Avery,
    Do you think Amanda and I did a good job? Well, I hope you did because it was very hard to keep looking at the camera. I also think that introduction and ending thing was cool.


  14. mrsdelgado says:

    Hello Marshall and Amanda! I am so impressed with your elapsed time video. Thank you for sharing it! I am going to show it to my third graders so they can learn your method as we study elapsed time ourselves. Keep up the great work Mr. Avery’s class! Way to go!

    Mrs. Delgado

  15. Ben P. says:

    Hi Amanda,

    I like the way you figured out the amount of time that elapsed. You are great on video.

    Ben (Amanda’s cousin)

  16. Ethan P. (Amanda's other favorite cousin) says:


    I wish that I had a video like this to watch when I was learning math. Nice job explaing how you figure out the amount of time that elapsed. I think it will help me. Ben and I are practicing doing it the way you guys showed us. It’s a lot easier your way. I liked your video! Have a good day.

    Ethan (Amanda’s cousin)

  17. Algnes Amanda's Aunt says:

    Dear class,

    Great elapsed time video’s Marshall and Amanda! I also really enjoyed this video about area as well! I was very impressed with all of your on camera speaking ability. Keep up the good work.

    Amanda’s Aunt Agnes

  18. Rebecca P. says:

    Amanda and Marshall,

    Love this video! Great job explaining elapsed time. Love watching you on video.

    Becky (Amanda’s cousin)

  19. Auntie Eileen says:

    Marshall and Amanda, you did an AWESOME job on the explanation of elapsed time problems! You should both consider a career in broadcasting or become math teachers. Keep up the good work. I can’t wait to see what is on the blog tomorrow.

    Auntie Eileen

  20. Justine says:

    Amanda and Marshall,

    You make math look so easy and fun! Your simple explanations were easy to follow. I practice along with the both of you. Thank you for the refresher!

    Amanda’s cousin Justine

  21. Ariel D. says:

    Dear Mr. Avery,

    The number line made it so much easier for me. You have such a creative mind. The video on the other blog is a way of subtracting.


  22. Susan says:

    Amanda, Marshall and Mr. Avery,

    Thank you so much for posting The Elapsed Time Video!
    It has helped me so much!!
    I had problems learning math in 3rd and 4th grade-it has held me back from doing a lot of things throughout my life. I am now 55 and just beginning to understand elapsed time…Thanks to your
    FANTASTIC explanation! I have one request that would help me and possibly others too. Would you please post a sample page of some problems with the answers worked out in a PDF format? I would appreciate that greatly. Amanda and Marshall…you are both so gifted in teaching that I am sure you will excel in whatever path you choose to pursue in life. Enjoy your studies…it really is the key to open the door to anywhere!

    Thank you again,

  23. Sue Downing says:

    Very creative and impressive video. It gave me an idea for a laminated fill-in-the-blanks timeline to help students visualize how to create their own. May I link to your webpage in a blog post about elapsed time?

  24. Mrs. H in NC says:

    Dear Amanda and Marshall,
    This is my third year teaching elapsed time to a group of third graders. Every year I “research” ways to teach elapsed time in a way that students will understand. I FOUND IT! Thank you so much for making this video. I can’t wait to share it with my students tomorrow morning!

    Thanks so much for providing and explaining a strategy that I can use for years to come.

    Mrs. H.

  25. Billie Jean says:

    Thank you so much for posting this on-line! We have a fourth grader and two third graders in our family this year. The third greaders picked up elapsed time in a snap but the fourth grader was so confused and getting very frustrated, in part because it didn’t make sense to him while his two sisters thought it was sooooo easy! After finding this method he has relaxed and feels comfortable doing elapsed time problems. In fact, when I came down this morning he was sitting at the kitchen table doing more of them just for fun because now it makes sense and he is enjoying the math. This is a really great approach and we appreciate that you have made it availble to others like this!

    Billie Jean

  26. Teri Rushford says:

    Thank you so much! We are always looking for another way to help our students!

  27. Mr Jackson says:

    Hi Guys! Thank you so much for this! I am a new teacher in the UK and so I am still learning about how to teach children these things. I can honestly say this video is perfect!!! It taught me perfectly and I think it will be great to show it to my class when we do this.

    Thanks guys and girls.

    Mr Jackson

  28. Felicity Ross says:

    I love this video! I have been looking for a way to teach elapsed time to my last few students who still aren’t getting it. I hope this will work for them. Thank you!!!

  29. HelloMissWright says:

    This is great! I’m going to post this to my classroom website to help my kiddos learn elapsed time. This is also a great examples of what I’ve been trying to get my kiddos to do-make their own learning videos explaining their math skills! Great job!

    • Mr. Avery says:

      Hi Miss Wright,

      We’re so glad that you’re going to add it to your website! We’re thrilled that it will help.

      If you make any math videos, we’d love to see them. We’d also love for you to add them to the Student Made Math Movies.

      Mr. Avery’s Class

  30. Marni Singer says:

    Hi Mr. Avery!

    Thank you so much to you and your students for that great video! I’m going to teach my students this strategy next week. What do you do if the minutes add up to more than 60?


    • Mr. Avery says:

      Hi Marni,

      If the minutes add up to more than 60 we talk about how to convert it into hours. We add our hour to the total hours in the center and then use our leftover minutes as our minute total. I hope this strategy helps your students!

      Mr. Avery

      • Marni Singer says:

        Thanks Mr. Avery!

        Did you also use this strategy to figure out beginning time when end time and duration were given, or to figure out end time when beginning time and duration were given?


        • Mr. Avery says:

          Hi Marni,

          We didn’t but you could definitely use this for that as well. You might have to make a few slight adjustments with it but I think it could work well. If you try it, I’d love to hear how it goes!

          Mr. Avery

  31. Ms. O'Regan's Class says:

    Thanks we found this video really helpful! From a class in Canada.

  32. Mrs. Conner says:

    I love this! I’m trying it with my students today!

  33. Ms. Cherry says:

    Thank you for sharing this. I’ve been searching for a concept that was logical and easy to understand. My children are schooled at home and we’ve used the K12 and PA Cyber curriculums and this is the clearest way I’ve seen elapsed time explained. It can be a rather tricky concept for young learners to grasp, but you’ve made it simple. Thank you again.

  34. Anonymous says:

    Awesome job Marshall and Amanda!

  35. Mary says:

    I am a third grade teacher and I was just scouring the internet for a lesson on how to present elapsed time on a number line. I found Amanda and Marshall. I can’t think of better presenters. My students will definitely be interested in seeing other students present something instead of the same old me. Thanks for sharing.

    • Mr. Avery says:

      Hi Mary,

      I’m so glad that you found this lesson beneficial! Marshall and Amanda did such an incredible job explaining this concept. I couldn’t have asked for two better students to help teach this to others!

      Mr. Avery

  36. Ms. Forney's Class says:

    Dear Amanda and Marshall – We finally understand how to do elapsed time on a number line!! Thanks for the lesson.
    Ms. Forney’s Math Class
    Wilson Creek Elementary
    Johns Creek , GA

  37. Mr. Ostrowski says:

    Thanks, Mr. Avery’s class! Our 3rd grade class watched this video to help them understand how to use an empty number line. They loved it! Now, they want to try more and more elapsed time problems.

  38. Mrs. Allen's Class says:

    Thanks so much to your class, along with Amanda and Marshall. The students in my class really enjoyed your video and we hope to learn from your teaching. Thank you so much.

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