The Time That Passes Between One Event and Another: Complete Guide for 3rd Grade

Master calculating elapsed time between events with these 5 detailed exercises including comprehensive explanations, rules, and visual learning aids.

Exercises: Calculating Time Between Events (1-3)
1 Simple Hour Elapsed Time
Exercise 1
Sarah started reading at 2:00 PM. She finished reading at 4:00 PM. How much time passed between when she started and finished reading?
Key Definitions:

Elapsed Time: The amount of time that passes between two events. It's calculated by subtracting the start time from the end time.

Start Time: The time when an event begins.

End Time: The time when an event finishes.

Method:
  1. Identify the start time and end time
  2. Make sure both times are in the same format (AM or PM)
  3. Subtract the start time from the end time
  4. State the answer with the correct time unit
Start Time
2:00 PM
End Time
4:00 PM
Elapsed Time
2 hours
Step 1: Identify the start and end times

Start time: 2:00 PM

End time: 4:00 PM

Step 2: Check if both times are in the same format

Both times are in PM format, so they can be directly compared

Step 3: Calculate the elapsed time

Elapsed time = End time - Start time

Elapsed time = 4:00 PM - 2:00 PM = 2 hours

Step 4: State the answer

2 hours passed between when Sarah started and finished reading

2 hours passed
Final answer:

2 hours passed between when Sarah started and finished reading.

Applied rules:

• Elapsed Time Formula: End time - Start time = Elapsed time

• Same Format: Both times must be in AM or PM

• Subtraction: Hours are subtracted from hours

2 Elapsed Time with Minutes
Exercise 2
A movie started at 3:15 PM and ended at 5:45 PM. How much time passed between the start and end of the movie?
Definition:

Minutes: Units of time where 60 minutes = 1 hour. When calculating elapsed time, handle hours and minutes separately.

Start Time
3:15 PM
End Time
5:45 PM
Elapsed Time
2 hours 30 minutes
Step 1: Identify the start and end times

Start time: 3:15 PM

End time: 5:45 PM

Step 2: Calculate hours and minutes separately

Hours: 5 - 3 = 2 hours

Minutes: 45 - 15 = 30 minutes

Step 3: Combine the results

Elapsed time = 2 hours and 30 minutes

Step 4: Verify the calculation

Check: 3:15 PM + 2 hours 30 minutes = 5:45 PM ✓

2 hours 30 minutes passed
Final answer:

2 hours and 30 minutes passed between the start and end of the movie.

Applied rules:

• Separate Calculation: Handle hours and minutes separately

• Same Format: Both times in PM format

• Verification: Add elapsed time to start time to check

3 Activity Duration Problem
Exercise 3
Emma's soccer practice started at 4:30 PM and lasted for 1 hour and 45 minutes. What time did her soccer practice end?
Definition:

Duration: The length of time an activity takes. To find the end time, add the duration to the start time.

Start Time
4:30 PM
Duration
1 hr 45 min
End Time
6:15 PM
Step 1: Identify what is given

Start time: 4:30 PM

Duration: 1 hour and 45 minutes

Step 2: Add the duration to the start time

Add hours first: 4:30 PM + 1 hour = 5:30 PM

Add minutes: 5:30 PM + 45 minutes = 5:75 PM

Step 3: Convert minutes to hours if necessary

5:75 PM = 5:60 PM + 15 minutes = 6:00 PM + 15 minutes = 6:15 PM

Step 4: State the final answer

Emma's soccer practice ended at 6:15 PM

Step 5: Verify the calculation

Check: 4:30 PM + 1 hour 45 minutes = 6:15 PM ✓

Soccer practice ended at 6:15 PM
Final answer:

Emma's soccer practice ended at 6:15 PM.

Applied rules:

• Addition: End time = Start time + Duration

• Minute Conversion: 60 minutes = 1 hour

• Verification: Check calculation by working backwards

Time Between Events Fundamentals
Elapsed Time = End Time - Start Time
Core Formula
Elapsed Time
End - Start
Time that passes
Duration
Activity Length
How long it takes
Time Units
60 min = 1 hr
Conversion factor
Key Concepts:

Elapsed Time: The time that passes between two events (end time - start time).

Duration: The length of time an activity takes.

AM/PM: Time formats for morning (AM) and afternoon/evening (PM).

Calculation Techniques:
  1. Identify Times: Find start and end times in the problem
  2. Check Format: Ensure both times are in same format (AM or PM)
  3. Calculate: Subtract start from end time
  4. Handle Minutes: If minutes go negative, borrow an hour
  5. State Answer: Include correct time units
Tip 1: Always check if times are in the same format (AM or PM).
Tip 2: When minutes go negative, borrow 60 minutes from the hour.
Tip 3: Draw a timeline to visualize the time span.
Tip 4: Always verify your answer by adding back the elapsed time.
Common Mistake: Forgetting to borrow when minutes go negative in subtraction.
Memory Aid: "End minus start equals time that has passed."
Essential Rules:

• Elapsed time = End time - Start time

• 60 minutes = 1 hour

  • Both times must be in same format (AM or PM)
  • Always include time units in your answer
    • Exercises: Advanced Time Calculations (4-5)
    4 Borrowing Minutes Problem
    Exercise 4
    A school play started at 7:20 PM and ended at 9:05 PM. How much time passed between the start and end of the play?
    Definition:

    Borrowing Minutes: When subtracting times and minutes in the end time are smaller than minutes in the start time, you must borrow 60 minutes from the hour.

    Start Time
    7:20 PM
    End Time
    9:05 PM
    Elapsed Time
    1 hour 45 minutes
    Step 1: Identify start and end times

    Start time: 7:20 PM

    End time: 9:05 PM

    Step 2: Notice the minute issue

    End minutes (5) is less than start minutes (20)

    We need to borrow 60 minutes from the hour

    Step 3: Borrow from the hour

    Change 9:05 PM to 8:65 PM (borrowed 60 minutes)

    Step 4: Calculate with borrowed time

    Hours: 8 - 7 = 1 hour

    Minutes: 65 - 20 = 45 minutes

    Step 5: State the answer

    Elapsed time = 1 hour and 45 minutes

    1 hour 45 minutes passed
    Final answer:

    1 hour and 45 minutes passed between the start and end of the play.

    Applied rules:

    • Borrowing Rule: When end minutes < start minutes, borrow 60 minutes

    • Time Conversion: 1 hour = 60 minutes

    • Verification: Check: 7:20 + 1:45 = 9:05 ✓

    5 Multi-Day Time Span Problem
    Exercise 5
    A train departed at 11:30 PM on Monday and arrived at 6:45 AM on Tuesday. How much time passed during the train journey?
    Definition:

    Multi-Day Time Span: Time that passes across different calendar days, requiring calculation of time from start to midnight, then from midnight to end.

    Departure
    11:30 PM Mon
    Arrival
    6:45 AM Tue
    Total Time
    7 hours 15 minutes
    Step 1: Identify the time periods

    From 11:30 PM Monday to 12:00 AM Tuesday = Part 1

    From 12:00 AM Tuesday to 6:45 AM Tuesday = Part 2

    Step 2: Calculate Part 1 (Monday night)

    From 11:30 PM to 12:00 AM = 30 minutes

    Step 3: Calculate Part 2 (Tuesday morning)

    From 12:00 AM to 6:45 AM = 6 hours 45 minutes

    Step 4: Add both parts together

    Total time = 30 minutes + 6 hours 45 minutes

    Total time = 6 hours 75 minutes

    Total time = 7 hours 15 minutes

    Step 5: Verify the answer

    Check: 11:30 PM + 7 hours 15 minutes = 6:45 AM ✓

    7 hours 15 minutes passed
    Final answer:

    7 hours and 15 minutes passed during the train journey.

    Applied rules:

    • Day Break: Calculate time in parts when crossing midnight

    • Minute Conversion: 60 minutes = 1 hour

    • Verification: Add elapsed time to start time to check

    Complete Time Between Events Summary
    Elapsed Time = End Time - Start Time
    Core Formula
    Key definitions:

    Elapsed Time: The amount of time that passes between two events (end time - start time).

    Duration: The length of time an activity takes.

    Time Span: The total time from start to finish of an activity.

    Complete methodology:
    1. Identify Times: Locate start and end times in the problem
    2. Check Format: Ensure both times are in same format (AM or PM)
    3. Handle Minutes: Borrow 60 minutes if needed for subtraction
    4. Calculate: Subtract start from end time
    5. Verify: Check your answer by adding back
    Tip 1: Draw a timeline to visualize the time span.
    Tip 2: Remember 60 minutes = 1 hour for conversions.
    Tip 3: Always include time units in your final answer.
    Tip 4: Verify by adding elapsed time to start time.
    Common errors: Forgetting to borrow minutes, mixing AM/PM formats, missing time units.
    Key memorization: End - Start = Elapsed Time, 60 min = 1 hour.
    Essential rules to remember:

    • Elapsed time = End time - Start time

    • 60 minutes = 1 hour

    • Borrow 60 minutes when end minutes < start minutes

    • Both times must be in same format (AM or PM)

    • Always include time units in your answer

    Questions & Answers

    Question: When I subtract times and the minutes go negative, what should I do? For example, if I have 3:15 - 2:45, the minutes would be 15 - 45 = -30.

    Answer: When minutes go negative, you need to borrow from the hour:

    • Take 1 hour from the hour part (3:15 becomes 2:75)
    • Add 60 minutes to the minutes part (15 + 60 = 75)
    • Now subtract normally: 2:75 - 2:45 = 0:30 = 30 minutes

    So 3:15 - 2:45 = 30 minutes. Remember: 1 hour = 60 minutes, so when you borrow 1 hour, you get 60 more minutes!

    This borrowing method works just like with regular subtraction when you need to borrow from the tens place.

    Question: How do I handle problems where the start time is in PM and the end time is in AM, like from 10:00 PM to 7:00 AM?

    Answer: This is a multi-day problem! You need to break it into parts:

    • From 10:00 PM to 12:00 AM (midnight) = 2 hours
    • From 12:00 AM to 7:00 AM = 7 hours
    • Total = 2 + 7 = 9 hours

    Alternatively, you can think of it as going from 10:00 PM to 10:00 AM (12 hours) and then subtracting the extra 3 hours from 7:00 AM to 10:00 AM, which gives you 12 - 3 = 9 hours.

    The key is recognizing when you cross midnight and handling the day change properly!

    Question: How can I practice calculating elapsed time at home? What are some real-life examples?

    Answer: There are many opportunities at home:

    • TV shows: How long is your favorite program?
    • Bedtime routines: How long does it take to get ready?
    • Meals: How long does dinner take from start to finish?
    • Activities: How long does homework take?
    • Travel: How long does a car trip take?

    Make it fun by keeping a time log of your daily activities and calculating how long each takes. You can also create a schedule and calculate time spans for different parts of your day!

    The more you practice with real situations, the better you'll get at managing time!