Elapsed Time

Shodor > Interactivate > Lessons > Elapsed Time


In this lesson, students will learn about elapsed time and how to find the elapsed time given the starting and ending time.


Upon completion of this lesson, students will:

  • understand the concept of elapsed time
  • be able to calculate elapsed time given the starting and ending time

Standards Addressed:

Student Prerequisites

  • Arithmetic: Students must be able to:
    • complete simple addition
  • Technological: Students must be able to:
    • perform basic mouse manipulations such as point, click and drag
    • use a browser for experimenting with the activities

Teacher Preparation

Students will need:

  • access to browser
  • paper and pencil

Key Terms

additionThe operation, or process, of calculating the sum of two numbers or quantities
elapsed timeA period of time that has passed, usually between a given starting time and ending time

Lesson Outline

  1. Focus and Review

    Open the lesson with this question, replacing times to make it more authentic:

    • We started math at 10 a.m. It is now 11 a.m. How long have we been doing math?
    • What do we call this time?

  2. Objectives

    Let the students know what they will be doing and learning today. Say something like this:

    • Today, class, we are going to learn what elapsed time is and how to calculate it.
    • We are going to use the computers to do this but please do not turn your computers on until I ask you to. I want to show you a little about this activity first.

  3. Teacher Input

    • Lead the students in a discussion about elapsed time.

  4. Guided Practice

    • Have the students draw starting and ending times on their Elapsed Time Record Sheet. Then instruct them to calculate the elapsed time.
    • Open your browser to the Elapsed Time applet. Explain to the students how to work the applet.

  5. Independent Practice

    • Have students answer 10 problems on their own.
    • Have the students answer the Exploration Questions while working with the applet.

  6. Closure

    • Discuss as a class what the students discovered while answering the exploration questions.

Alternate Outline

If there is only one computer, this lesson can be modified in the following ways:

  • The teacher can prepare problems by given students various starting and ending times. The students can then discuss methods for finding elapsed time.
  • Students who need additional help can use the applet after completing the problems on paper.

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