Elapsed Time

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SWBAT write and solve elapsed time problems using an interactive clock model.

Big Idea

Finding ways to make the abstract more concrete provides an entry point for learning.


10 minutes

Yesterday we created a visual example of parts of a clock. Who can remind me what they are?

We watch the BrainPop Elapsed Time interactive video. This is a subscription service, but there are other free resources available. One possible choice is Elapsed Time by Common Core 4 Kids.


45 minutes

Some of the best problems I have ever read have come from all of you! The way you think about questions and problem solving has really blown me away. Today I want you to write your own elapsed time problems and we will use them for your classmates to solve.

Who can help me think about what types of things we do each day that we might write about? Here I want students to relate time to their daily activities. It would be helpful to record student responses on the board so that students who are struggling to generate ideas have a starting point. If students are struggling to find ways to relate time to their daily life, it would be appropriate to stretch students by creating scenarios (We started math at X time, and we will finish at Y time. How much time will we spend on math today?) I want students to think about getting ready for school, going to PE, lunch and recess, eating dinner and activities that they do in the evenings and weekends that they could include in their problems. 

Remember to use your clock helpers you created yesterday to solve problems in greater chunks of time instead of counting minute by minute (MP6)!

Students will return to their seats and write word problems involving elapsed time (MP1). I believe that word problems create a more challenging activity, and by crafting word problems it helps students better understand how to think critically about solving problems. It can be easy to identify struggling students based on the language or types of problems they create. When I see this in students I begin working with them on language, and if necessary, provide a list of vocabulary that could be helpful for them (How much time has passed... How long will I spend.... I started at.... I ended at....) 

I will give them 20 minutes to write and then re-pass out the problems for students to solve for the other 20 minutes.  


5 minutes

Who can tell me what elapsed time means? (I expect students to respond that it is the amount of time that has passed during a given activity or time frame). 

What was one way that you used to solve your word problems today? (I expect to hear responses related to breaking the time into parts the time by quarter hours, half hours or full hours or by showing moves on a clock on their paper etc)

What types of things made it difficult for you to solve problems? (I always like to discuss problems that students faced during the activity. This gives me a good reference for common themes or issues and it also lets other students know that they're not the only ones who may have come across a particular issue. By promoting these discussions I attempt to show students that we all struggle, which is part of the learning process, and that we all find paths to solving in different ways. Students can learn a lot from the discussions around how others have solved problems.