Time Travel Teacher Guide Time Travel Theatre
Teacher Facilitation Guide
Grade 4 • Math
Lesson Objective
Students will be able to subtract time intervals in hours and minutes by using the borrowing method, specifically converting 1 hour into 60 minutes when the minute value is insufficient.
Required Materials
Cinema Calculation Slides
Movie Marathon Worksheet
Base-60 Anchor Chart
Whiteboards/Markers
Key Concepts
Base-60: The system used for time (vs. Base-10).Regrouping: "Borrowing" 1 hour as 60 mins.Intervals: The space between two points in time.
Instructional Sequence
00-05 mins: Base-10 vs Base-60 Warm-up
Display a standard subtraction problem (52 - 38) next to a time problem (5h 15m - 2h 45m). Discuss why borrowing 10 doesn't work for the clock.
Question: "If I take an hour away, how many minutes do I get?"
05-15 mins: The Feature Presentation (Video)
Watch the subtraction section of the video. **Crucial Pause at 4:00 mark.**
Turn and Talk: "Why did he add 60 instead of 100?"
15-35 mins: The Movie Marathon Activity
Students solve word problems using vertical subtraction. Emphasize setting up columns (Hours | Minutes) and showing the cross-out of hours clearly.
35-40 mins: Find the Error
Display a "villain" solution where someone borrowed 100. Students must act as "Time Detectives" to fix the error.
Scaffolding & Extension
Support
Provide clock manipulatives or "minute strips" to visually show 60 units being moved. Use the Anchor Chart as a desk reference.
Extend
Challenge students with problems spanning more than 12 hours or including AM/PM transitions, requiring multi-step conversion.
Movie Marathon Worksheet Movie Marathon
Challenge Worksheet • Time Subtraction
NAME:
DATE:
Scenario: The Free Time Feature
You have exactly 5 hours and 15 minutes of free time today. You want to watch a feature film that is 2 hours and 40 minutes long. How much free time will you have left for snacks after the movie?
1
Set up the scenario above as a vertical subtraction problem.
HOURS
MINS
2
Movie: "The Galactic Race"
Total Time: 4h 10m
3
Movie: "Quest for the Clock"
Total Time: 6h 05m
4
Double Feature Challenge
You have a 7 hour and 20 minute flight. You watch two short films. The first film is 1h 50m and the second is 2h 15m. How much time is left on your flight? (Show all steps!)
The Exit Ticket
When we "borrow" an hour in time subtraction, why do we add 60 to the minutes instead of 10 or 100?
Base-60 Anchor Chart Base-60 Secret
The Rule of the Clock
THE GOLDEN RULE
1 Hour
=
60 Minutes
Standard Subtraction
4 5 +10 2
- 3 8
1 4
We borrow 10
Time Subtraction
Hrs 7 8 Mins +60 15
- 4 45
3 30
We borrow 60!
The Borrowing Checklist
Subtract 1 from the Hours column
Add 60 to the Minutes column
Finish the subtraction as usual!
Cinema Calculation Slides Cinema
Calculations
Subtraction with Borrowing
FEATURING: BASE-60 MATH
?
Warm-Up: The Base Duel
Standard Subtraction
52 - 38 = ?
When we borrow, we get 10.
Time Subtraction
5:15 - 2:45 = ?
Will borrowing 10 work here?
The Feature Film
WATCH: SUBTRACTION
Embedded media
Wait for the 4:00 mark for the big secret!
Turn & Talk
"In the video, why did he add 60 to the minutes instead of 100?"
Discuss with your partner
The Borrowing Strategy
1
CRACK IT
Take 1 Hour away from the Hours column.
2
CONVERT IT
Change that hour into 60 Minutes.
3
SOLVE IT
Add the 60 to your minutes and subtract.
Time Detectives: Find the Error!
Case #402
Hrs 3 4 Mins +100 15
- 1 : 40
What went wrong in this calculation?
Movie Marathon Answer Key Movie Marathon
OFFICIAL ANSWER KEY • TEACHER RESOURCE
Verified Solutions
Teacher Note:
Check that students are explicitly showing the cross-out in the Hours column and writing +60 above the Minutes. The process is as important as the final answer!
1
Scenario Problem
5h 15m - 2h 40m
4 5h +60 75m
- 2h 40m
2h 35m
2
Galactic Race
4h 10m - 1h 45m
3 4h +60 70m
- 1h 45m
2h 25m
3
Quest for the Clock
6h 05m - 3h 20m
5 6h +60 65m
- 3h 20m
2h 45m
4
Double Feature Challenge
Step 1: Total Movie Time
1h 50m + 2h 15m =
Step 2: Subtraction
7h (6) 20m (80)
- 4h 05m
3h 15m
Exit Ticket Answer Guidance:
"We add 60 because time is based on 60 minutes in 1 hour (Base-60). In normal math, we borrow 10 because our number system is Base-10. If we borrowed 100 on a clock, we would be adding almost 2 full hours instead of just 1!"
