Basic Math

Time | Third Grade

🕐 Time - Grade 3

Understanding Time!

Time helps us know when things happen! We use clocks, calendars, and schedules to measure and organize time.

Units of Time:
• 60 seconds = 1 minute
• 60 minutes = 1 hour
• 24 hours = 1 day
• 7 days = 1 week
• 12 months = 1 year
• 365 days = 1 year (366 in leap year)

🕐 Match Analogue Clocks and Times

What is an Analogue Clock?

An analogue clock (also called analog) has a round face with numbers 1-12 and two or three hands that move to show time!

Parts of an Analogue Clock:
Hour Hand - Short, thick hand (shows hours)
Minute Hand - Long, thin hand (shows minutes)
Second Hand - Very thin hand (shows seconds)
Numbers - 1 to 12 around the clock
Tick Marks - Small lines between numbers

How to Read an Analogue Clock:

  1. Find the hour hand - The short hand shows the hour
  2. Find the minute hand - The long hand shows minutes
  3. Read the hour - What number is the short hand pointing to or past?
  4. Read the minutes - Count by 5s where the long hand points

Minute Counting Guide:

12 → 0 minutes (o'clock)
1 → 5 minutes
2 → 10 minutes
3 → 15 minutes (quarter past)
4 → 20 minutes
5 → 25 minutes
6 → 30 minutes (half past)
7 → 35 minutes
8 → 40 minutes
9 → 45 minutes (quarter to)
10 → 50 minutes
11 → 55 minutes

💡 Formula: Minutes = Number × 5 (for each hour mark)

🔢 Match Digital Clocks and Times

What is a Digital Clock?

A digital clock shows time using numbers in this format: HOURS:MINUTES

3:45
↓ ↓
Hours : Minutes

Reading Digital Time:

4:00 → Four o'clock
4:15 → Four fifteen (or quarter past four)
4:30 → Four thirty (or half past four)
4:45 → Four forty-five (or quarter to five)
4:25 → Four twenty-five

Converting Between Analogue and Digital:

Analogue ClockDigital ClockHow to Say It
Hour hand at 3, minute hand at 123:00Three o'clock
Hour hand between 3 & 4, minute hand at 33:15Quarter past three
Hour hand between 3 & 4, minute hand at 63:30Half past three
Hour hand between 3 & 4, minute hand at 93:45Quarter to four

✏️ Read Clocks and Write Times

Steps to Read and Write Time:

  1. Read the hour - Look at the short hand
  2. Read the minutes - Look at the long hand
  3. Write in digital format - HOURS:MINUTES
  4. Add AM or PM - Is it morning/afternoon?

Special Times to Remember:

12:00 → Noon (midday) or Midnight
:15 → Quarter past
:30 → Half past
:45 → Quarter to (next hour)
:00 → O'clock (on the hour)

Writing Time in Words:

Method 1: Say the hour, then the minutes
7:25 → Seven twenty-five

Method 2: Use "past" or "to"
7:25 → Twenty-five minutes past seven
7:55 → Five minutes to eight

🌅🌙 A.M. or P.M.

What Do A.M. and P.M. Mean?

A.M. = Ante Meridiem = "Before Noon"
(From midnight 12:00 AM to noon 11:59 AM)

P.M. = Post Meridiem = "After Noon"
(From noon 12:00 PM to midnight 11:59 PM)

A.M. Times (Morning):

12:00 AM → Midnight
6:00 AM → Early morning (sunrise)
8:00 AM → Breakfast time
11:00 AM → Late morning
11:59 AM → Just before noon

P.M. Times (Afternoon/Evening/Night):

12:00 PM → Noon (midday)
1:00 PM → Afternoon begins
6:00 PM → Evening (dinner time)
9:00 PM → Night time
11:59 PM → Just before midnight

How to Choose A.M. or P.M.:

  1. Think about the activity - When does it usually happen?
  2. Morning activities → Use A.M. (breakfast, going to school)
  3. Afternoon/Evening activities → Use P.M. (lunch, dinner, bedtime)

💡 Remember: 12 PM is noon (lunch), 12 AM is midnight (sleep)!

⏱️ Elapsed Time

What is Elapsed Time?

Elapsed time is the amount of time that passes between a start time and an end time!

\(\text{Elapsed Time} = \text{End Time} - \text{Start Time}\)

Methods to Find Elapsed Time:

Method 1: Counting Up

Start at the beginning time and count forward to the end time

Example: From 2:15 PM to 4:45 PM

2:15 PM → +45 min → 3:00 PM
3:00 PM → +1 hour → 4:00 PM
4:00 PM → +45 min → 4:45 PM

Total: 45 min + 1 hour + 45 min = 2 hours 30 minutes ✓

Method 2: Subtraction

Subtract the start time from the end time

Example: From 9:20 AM to 11:45 AM

Hours: 11 - 9 = 2 hours
Minutes: 45 - 20 = 25 minutes

Elapsed Time: 2 hours 25 minutes ✓

Method 3: Number Line

Draw a number line and jump from start to end, counting the time

Other Elapsed Time Formulas:

\(\text{End Time} = \text{Start Time} + \text{Elapsed Time}\)

\(\text{Start Time} = \text{End Time} - \text{Elapsed Time}\)

📖 Elapsed Time Word Problems

Steps to Solve:

  1. Read carefully - What is the question asking?
  2. Find the times - Start time and end time
  3. Decide what to find - Elapsed time? Start time? End time?
  4. Choose a method - Counting up, subtraction, or number line
  5. Calculate - Do the math
  6. Write the answer - Include hours and minutes

Example Problems:

Problem 1: Find Elapsed Time

Ravi starts his homework at 4:30 PM and finishes at 6:15 PM. How long did he work on his homework?

Start Time: 4:30 PM
End Time: 6:15 PM

Method: Counting Up
4:30 PM → +30 min → 5:00 PM
5:00 PM → +1 hour → 6:00 PM
6:00 PM → +15 min → 6:15 PM

Total: 30 + 60 + 15 = 105 minutes = 1 hour 45 minutes ✓

Problem 2: Find End Time

A movie starts at 7:15 PM and runs for 2 hours 30 minutes. What time does it end?

Start Time: 7:15 PM
Duration: 2 hours 30 minutes

Calculation:
7:15 PM + 2 hours = 9:15 PM
9:15 PM + 30 minutes = 9:45 PM

Answer: The movie ends at 9:45 PM ✓

Problem 3: Find Start Time

School ends at 3:30 PM. If the last class was 45 minutes long, what time did it start?

End Time: 3:30 PM
Duration: 45 minutes

Calculation:
3:30 PM - 45 minutes
3:30 PM - 30 min = 3:00 PM
3:00 PM - 15 min = 2:45 PM

Answer: The class started at 2:45 PM ✓

🔄 Time Patterns

What are Time Patterns?

Time patterns are sequences where time increases or decreases by a regular amount!

Types of Time Patterns:

Pattern 1: Adding Minutes

Example: Add 15 minutes each time
2:00, 2:15, 2:30, 2:45, 3:00, 3:15...
Pattern: +15 minutes

Pattern 2: Adding Hours

Example: Add 2 hours each time
8:00 AM, 10:00 AM, 12:00 PM, 2:00 PM, 4:00 PM...
Pattern: +2 hours

Pattern 3: Mixed Patterns

Example: Add 1 hour 30 minutes each time
1:00, 2:30, 4:00, 5:30, 7:00...
Pattern: +1 hour 30 minutes

How to Find the Pattern:

  1. Look at the first two times - Find the difference
  2. Check the next times - Is the difference the same?
  3. Identify the rule - What is being added or subtracted?
  4. Continue the pattern - Apply the rule to find next times

📅 Read a Calendar

Parts of a Calendar:

Month Name - January, February, March...
Year - 2025, 2026...
Days of the Week - Sunday, Monday, Tuesday...
Dates - 1, 2, 3... up to 28, 29, 30, or 31
Weeks - Rows showing 7 days

Months of the Year:

1. January (31 days)2. February (28/29 days)3. March (31 days)
4. April (30 days)5. May (31 days)6. June (30 days)
7. July (31 days)8. August (31 days)9. September (30 days)
10. October (31 days)11. November (30 days)12. December (31 days)

Using a Calendar:

  1. Find the date - Look for the number in the calendar
  2. Find the day of week - Check which column it's in
  3. Count days between dates - Count forward or backward
  4. Find dates before/after - Move days forward or back

💡 Rhyme to Remember:
"30 days has September, April, June, and November.
All the rest have 31, except February alone!"

📋 Reading Schedules

What is a Schedule?

A schedule is a list or table that shows when activities or events happen!

Example: School Schedule

TimeActivity
8:00 AM - 8:45 AMMaths
8:45 AM - 9:30 AMEnglish
9:30 AM - 9:45 AMBreak
9:45 AM - 10:30 AMScience
10:30 AM - 11:15 AMSocial Studies

How to Read a Schedule:

  1. Find the time column - Shows when things happen
  2. Find the activity column - Shows what happens
  3. Match time with activity - Read across the row
  4. Find durations - Calculate time between start and end

Questions About the Schedule:

Q1: What time does Maths class start?
A: 8:00 AM ✓

Q2: How long is the English class?
A: 9:30 - 8:45 = 45 minutes ✓

Q3: What subject is at 10:00 AM?
A: Science (9:45 AM - 10:30 AM) ✓

📏 Timelines

What is a Timeline?

A timeline is a line that shows events in the order they happen over time!

Events are marked on the line from earliest (left) to latest (right).

Example Timeline: A School Day

8:00 AM ──── 10:00 AM ──── 12:00 PM ──── 2:00 PM ──── 3:30 PM
   ↓              ↓              ↓              ↓              ↓
School       Break      Lunch      Sports     Home
Starts                                                Time

Reading a Timeline:

  1. Start at the left - This is the earliest time/event
  2. Move to the right - Events happen in order
  3. Read the labels - What happened at each mark?
  4. Check the scale - How much time between marks?
  5. Calculate durations - Find time between events

Timeline Questions:

Q1: What time was the break?
A: 10:00 AM ✓

Q2: How long between school starting and lunch?
A: 12:00 PM - 8:00 AM = 4 hours ✓

Q3: What happened after lunch?
A: Sports at 2:00 PM ✓

Creating a Timeline:

  1. List all events - Write them in order
  2. Draw a line - Left to right
  3. Mark equal spaces - For equal time intervals
  4. Label each point - Add time and event name
  5. Add a title - Tell what the timeline shows

📝 Important Formulas Summary

Time Conversions:

\(1 \text{ minute} = 60 \text{ seconds}\)
\(1 \text{ hour} = 60 \text{ minutes}\)
\(1 \text{ day} = 24 \text{ hours}\)
\(1 \text{ week} = 7 \text{ days}\)
\(1 \text{ year} = 12 \text{ months} = 365 \text{ days}\)

Elapsed Time Formulas:

\(\text{Elapsed Time} = \text{End Time} - \text{Start Time}\)

\(\text{End Time} = \text{Start Time} + \text{Elapsed Time}\)

\(\text{Start Time} = \text{End Time} - \text{Elapsed Time}\)

Clock Reading:

\(\text{Minutes} = \text{Hour number} \times 5\)
(For reading analogue clocks)

💡 Quick Learning Tips

  • Hour hand is short, minute hand is long
  • Each number on analogue clock = 5 minutes
  • Digital time format: HOURS:MINUTES (3:45)
  • A.M. = morning (before noon), P.M. = afternoon/night (after noon)
  • 12:00 PM = noon, 12:00 AM = midnight
  • Elapsed time = End time - Start time
  • Count up method: Jump from start to end time
  • Subtraction method: Subtract hours, then minutes
  • Time patterns: Look for what's being added each time
  • 30 days: April, June, September, November
  • 31 days: January, March, May, July, August, October, December
  • February: 28 days (29 in leap year)
  • Schedules show when activities happen
  • Timelines show events in order from left to right
  • Practice reading clocks every day!
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