Timeline Solutions for Time Problems
Students will be able to solve sums and differences in time problems using number lines.
- Show your students a number line paper strip that goes from 1 to 60 by increments of 1, curl it up into a circle and ask them, “In what ways might this be related to a clock?”
- Have students turn and tell a neighbour their ideas. Then allow classmates to volunteer their thoughts, or something they overheard as you write down any academic terms related to time.
Explicit Instruction/Teacher modeling(10 minutes)
- Explain how the 1 to 60 Number lineIs similar to minute measurements around the circle of an analog clock. The number line can be used as a tool to find the passing of time. Point out the differences between an open number line, and another in one-minute increments (this is the number line students will be working with).
- Ask your students to consider 5:30 on such a timeline, by finding 30 and marking the point (note that the timeline represents the hour of five o’clock).
- Ask your students, "If you wanted to know what time 15 minutes earlier would be, which direction would you go?" Spread out your arms and ask students to point which direction.
- Looking at the number line, clarify that moving backwards towards the one, takes you back within the hour, and moving forward towards the 60 takes you ahead towards the next hour.
- Query your class, “What happens when you pass 60 either way, left or right?” Have them turn to tell a neighbour their thoughts.
- Allow students to share out whole class. Clarify that going past 60 moves into the next hour beginning at one minute past, and moving backwards past the 60 takes you into a previous hour to decreasingly count from 60.
Guided practise(5 minutes)
- Hand out and preview the Solving Time Problems Between Hours with Number Lines worksheet with your students.
- Read through the example with your class and answer any clarifying questions.
Independent working time(15 minutes)
- Students should complete the exercises on the Solving Time Problems Between Hours with Number Lines worksheet independently or in strategic partnerships
- Enrichment: Students can draft two new problems: One requiring adding into a new hour and another requiring subtraction into a previous hour.
- Support: If students have trouble adding or subtracting across hours, modify the Solving Time Problems Between Hours with Number Lines worksheet exercises to include single digit numbers (i.e. “...if she had an eight minute drive..” opposed to “...if she had a 45 minute drive…”).
- Using an interactive digital whiteboard, review and solve time interval problems with your class using number lines from 1 to 60 in one unit increments.
- Use Google Spreadsheets to make a sheet of number lines from 1 to 60 by selecting various cell bordering options.
- Draft a half sheet with three number lines and a dot marking different minutes. Give students a particular time, and have them calculate minutes needed to arrive at your time. Provide opportunities to cross hours backwards, forwards and within the hour (see materials section).
Review and closing(10 minutes)
- Review the answers for Solving Time Problems Between Hours with Number Lines with your class by allowing students to challenge or call on a friend for assistance.
- Discuss the Think About It question, noting academic language and key insights on poster paper to reference later.