3.GM.3.2
3.GM.3.2 Determine the solutions to problems involving addition and subtraction of time in intervals of five minutes, up to one hour, using pictorial models, number line diagrams, or other tools.
In a Nutshell
This objective introduces elapsed time. It is vital that students understand that you can add or subtract time to help solve problems in real-world contexts. Students need plenty of experience with tools and strategies that will help them understand problem-solving with time conceptually and make the connections necessary for determining elapsed time.
Student Actions
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Teacher Actions
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Create and justify models of addition or subtraction of time, using various tools such as a number line, pictures, and clocks.
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Develop strategies for problem-solving such as reading the context, drawing a picture, or acting out the problem, to accurately find the solution.
- Communicate solutions mathematically to peers and justify the answer using a variety of tools and strategies, such as skip counting or drawing a clock.
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Pose purposeful questions to help students recall prior knowledge and justify their thinking. Questions may include asking students different ways to find the solution.
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Implement real-life tasks where you would need to be able to add or subtract time, e.g. Ricky leaves school at 3:25. It takes him 15 minutes to get home. What time is it when Ricky arrives home?
- Support productive struggle as students explore a variety of methods to solve the problems, such as a number line instead of a clock.
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Key Understandings
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Misconceptions
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Time is considered a measurement. Because of that, time can be added or subtracted.
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When the hour or minute hand is moving “clockwise”, time is being added. When the hour or minute hand is moving “counterclockwise”, time is subtracted.
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When the minute hand passes the 12 on the clock, they have moved to the next hour.
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When the hour hand moves from 12 to 1 o’clock, a.m. turns to p.m. or vice versa.
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Add time like regular numbers, (e.g. If you start at 11:50 and you add 20 minutes, the time would be 11:70.)
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Only the minutes change when adding or subtracting time, (e.g. If you start at 4:40 and you add 30 minutes, the time would be 4:10.)
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Knowledge Connections
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Prior Knowledge
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Leads to
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Determine elapsed time. (4.GM.3.1)
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Convert one measure of time to another including seconds to minutes, minutes to hours, hours to days, and vice versa, using various models. (4.GM.3.2)
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| Sample Assessment Items |
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The Oklahoma State Department of Education is releasing sample assessment items to illustrate how state assessments might be designed to measure specific learning standards/objectives. These examples are intended to provide teachers and students with a clearer understanding of how the state assesses Oklahoma's academic standards and their objectives. It is important to note that these sample items are not intended to be used for diagnostic or predictive purposes. Ways to incorporate the items.
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