Mathematics

Time

Class 4 | CBSE / NCERT / ICSE

🎯 Learning Objectives

Read time to the nearest 5 minutes, including quarter past and quarter to.
Find the duration between a start time and an end time.
Convert hours to minutes and minutes to hours.
Understand the 24-hour clock format.
Solve problems related to calendars.

📖 Let Us Begin!

In Class 3, you learned to read time using hours and half hours. You also learned about a.m. and p.m. Now in Class 4, we will read time more precisely -- to every 5 minutes!

Think about your school day. The bell rings at 7:45 a.m. and the first period ends at 8:25 a.m. How long was the period? We will learn to find such durations. We will also learn the 24-hour clock used in railways and airports across India.

Image: Two analog clocks showing different times, with labels for hour hand, minute hand. One clock shows "quarter past 3" (3:15) and the other shows "half past 7" (7:30).
Title: Reading a Clock

Reading Time to 5 Minutes

The minute hand moves from one number to the next in 5 minutes. Count by 5s from 12 to read the minutes.

Quarter past = 15 minutes past the hour. Quarter to = 15 minutes before the next hour.

Example

Example 1:

If the hour hand is between 3 and 4, and the minute hand is on 3, the time is 3:15 or quarter past 3.

Example

Example 2:

If the hour hand is near 9 and the minute hand is on 9, the time is 8:45 or quarter to 9.

Think: The minute hand is on 7. How many minutes past the hour is it?

Finding Duration

Duration is the amount of time between a start time and an end time. Count forward from the start time to the end time.

Example

Example 3: A cricket match starts at 2:30 p.m. and ends at 5:15 p.m. How long was the match?

From 2:30 to 5:00 = 2 hours 30 minutes.

From 5:00 to 5:15 = 15 minutes.

Total duration = 2 hours 45 minutes.

Example

Example 4: Meena starts her homework at 4:10 p.m. and finishes at 5:00 p.m. How long did she study?

From 4:10 to 5:00 = 50 minutes.

Converting Hours and Minutes

1 hour = 60 minutes. To convert hours to minutes, multiply by 60. To convert minutes to hours, divide by 60.

Example

Example 5: Convert 3 hours to minutes.

3 x 60 = 180 minutes.

Example

Example 6: Convert 150 minutes to hours and minutes.

150 / 60 = 2 hours and 30 minutes (since 2 x 60 = 120, and 150 - 120 = 30).

Answer: 2 hours 30 minutes.

The 24-Hour Clock

In the 24-hour clock, we do not use a.m. or p.m. The hours go from 00:00 (midnight) to 23:59.

For times after 12 noon, add 12 to the hour. For example, 3:00 p.m. = 15:00 hours.

12-Hour Clock	24-Hour Clock
12:00 midnight	00:00
6:30 a.m.	06:30
12:00 noon	12:00
4:15 p.m.	16:15
9:45 p.m.	21:45

Think: The Rajdhani Express departs at 16:50. What time is that in the 12-hour clock?

Calendar Problems

Remember: 1 year = 12 months = 365 days (366 in a leap year). 1 week = 7 days.

Months with 31 days: January, March, May, July, August, October, December.

Months with 30 days: April, June, September, November. February has 28 or 29 days.

Example

Example 7: How many days are there from 10th March to 25th March?

Count from 10th to 25th: 25 - 10 = 15 days.

📝 Key Words

Word	Meaning
Duration	The amount of time from start to end
Quarter Past	15 minutes after the hour
Quarter To	15 minutes before the next hour
24-Hour Clock	A time system that counts hours from 0 to 23
Calendar	A chart showing days, weeks, and months of a year

⭐ Key Points to Remember

Count by 5s on the clock face to read minutes.
Quarter past = 15 min past. Quarter to = 15 min before the next hour.
1 hour = 60 minutes. To find duration, count forward from start to end.
24-hour clock: add 12 to p.m. hours (e.g., 3 p.m. = 15:00).
Know the number of days in each month for calendar problems.

Finished learning? Now test what you know!

🎯 Quick Quiz — Test Yourself!

Answer these 8 questions about time. Read each one carefully and pick the best answer!

Score: 0 / 8

1. How many minutes are there in 1 hour?

1 hour = 60 minutes.

2. "Quarter past" an hour means how many minutes past?

Quarter past means 15 minutes past the hour.

3. "Half past" an hour means how many minutes past?

Half past means 30 minutes past the hour.

4. In the 24-hour clock, what time is 3 p.m.?

For p.m. hours, add 12: 3 + 12 = 15, so 3 p.m. = 15:00.

5. "Quarter to" an hour means how many minutes before the next hour?

Quarter to means 15 minutes before the next hour.

6. How many minutes are there in 2 hours?

2 hours × 60 minutes = 120 minutes.

7. A film starts at 4:00 p.m. and ends at 6:00 p.m. How many hours long is it?

From 4:00 to 6:00 is 2 hours.

8. How do you convert a p.m. time to the 24-hour clock?

Add 12 to p.m. hours to get the 24-hour clock time (e.g. 3 p.m. = 15:00).

✏️ Practice Questions

A. Fill in the Blanks

1. Quarter past 6 means .

2. Quarter to 10 means .

3. 2 hours = minutes.

4. 240 minutes = hours.

5. 5:30 p.m. in 24-hour clock = .

B. Find the Duration

1. Start: 8:15 a.m., End: 10:45 a.m. Duration =

2. Start: 3:00 p.m., End: 5:30 p.m. Duration =

3. Start: 11:20 a.m., End: 1:05 p.m. Duration =

C. Convert to 24-Hour Clock

1. 7:00 a.m. =

2. 2:45 p.m. =

3. 11:30 p.m. =

4. 12:15 a.m. =

D. Multiple Choice Questions

1. How many minutes are there in 3 hours 20 minutes?

(a) 180(b) 200(c) 320(d) 150

2. What is 18:00 in the 12-hour clock?

(a) 6:00 a.m.(b) 8:00 p.m.(c) 6:00 p.m.(d) 8:00 a.m.

3. How many days are there in the month of November?

(a) 28(b) 30(c) 31(d) 29

E. Word Problems

1. A train departs from Delhi at 14:30 and arrives in Jaipur at 19:15. How long is the journey?

2. Rohan's school starts at 7:45 a.m. and ends at 1:30 p.m. How many hours and minutes is his school day?

3. Sita's birthday is on 18th April. Her friend's birthday is on 5th May. How many days are between the two birthdays?

🎨 Fun Activity -- My Day in 24-Hour Time

Write the time of each activity in both 12-hour and 24-hour format.

Activity	12-Hour Time	24-Hour Time
Wake up
Reach school
Lunch
Play time
Go to bed

Want to review the lesson again?

🎯 Learning Objectives

Read time to the nearest 5 minutes, including quarter past and quarter to.
Find the duration between a start time and an end time.
Convert hours to minutes and minutes to hours.
Understand the 24-hour clock format.
Solve problems related to calendars.

📖 Introduction

In Class 3, you learned to read time using hours and half hours. Now in Class 4, we will read time more precisely — to every 5 minutes! We will learn to find durations and understand the 24-hour clock used in Indian railways and airports.

[Image: Reading a Clock — Two analog clocks showing "quarter past 3" (3:15) and "half past 7" (7:30) with labels for hour hand and minute hand]

Reading Time to 5 Minutes

Ex 1: Hour hand between 3 and 4, minute hand on 3 → time is 3:15 (quarter past 3).

Ex 2: Hour hand near 9, minute hand on 9 → time is 8:45 (quarter to 9).

Finding Duration

Ex 3: Cricket match: 2:30 p.m. to 5:15 p.m. → 2:30 to 5:00 = 2 hr 30 min + 5:00 to 5:15 = 15 min → Total = 2 hr 45 min.

Ex 4: Meena's homework: 4:10 to 5:00 = 50 minutes.

Converting Hours and Minutes

1 hour = 60 minutes.

Ex 5: 3 hours = 3 × 60 = 180 minutes.

Ex 6: 150 minutes = 2 hours 30 minutes (150 ÷ 60 = 2 remainder 30).

The 24-Hour Clock

For times after 12 noon, add 12 to the hour. No a.m./p.m. needed.

12-Hour	24-Hour
12:00 midnight	00:00
6:30 a.m.	06:30
12:00 noon	12:00
4:15 p.m.	16:15
9:45 p.m.	21:45

Calendar Facts

1 year = 12 months = 365 days (366 in leap year). 31 days: Jan, Mar, May, Jul, Aug, Oct, Dec. 30 days: Apr, Jun, Sep, Nov. Feb = 28 or 29.

Key Words

Word	Meaning
Duration	Time from start to end
Quarter Past	15 minutes after the hour
Quarter To	15 minutes before the next hour
24-Hour Clock	Hours from 0 to 23
Calendar	Chart showing days, weeks, months

⭐ Key Points to Remember

Count by 5s on the clock face to read minutes.
Quarter past = 15 min past. Quarter to = 15 min before the next hour.
1 hour = 60 minutes. Duration: count forward from start to end.
24-hour clock: add 12 to p.m. hours (3 p.m. = 15:00).
Know the number of days in each month for calendar problems.

A. Fill in the Blanks

1. Quarter past 6 means .

2. Quarter to 10 means .

3. 2 hours = minutes.

4. 240 minutes = hours.

5. 5:30 p.m. in 24-hour clock = .

B. Find the Duration

1. Start: 8:15 a.m., End: 10:45 a.m. Duration =

2. Start: 3:00 p.m., End: 5:30 p.m. Duration =

3. Start: 11:20 a.m., End: 1:05 p.m. Duration =

C. Convert to 24-Hour Clock

1. 7:00 a.m. =

2. 2:45 p.m. =

3. 11:30 p.m. =

4. 12:15 a.m. =

D. Multiple Choice Questions

1. How many minutes in 3 hours 20 minutes?

(a) 180(b) 200(c) 320(d) 150

2. What is 18:00 in 12-hour clock?

(a) 6:00 a.m.(b) 8:00 p.m.(c) 6:00 p.m.(d) 8:00 a.m.

3. How many days in November?

(a) 28(b) 30(c) 31(d) 29

E. Word Problems

1. A train departs from Delhi at 14:30 and arrives in Jaipur at 19:15. How long is the journey?

2. Rohan's school starts at 7:45 a.m. and ends at 1:30 p.m. How many hours and minutes is his school day?

3. Sita's birthday is on 18th April. Her friend's birthday is on 5th May. How many days between?

🎨 Activity — My Day in 24-Hour Time

Activity	12-Hour Time	24-Hour Time
Wake up
Reach school
Lunch
Play time
Go to bed

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Time

🎯 Learning Objectives

📖 Let Us Begin!

Reading Time to 5 Minutes

Finding Duration

Converting Hours and Minutes

The 24-Hour Clock

Calendar Problems

📝 Key Words

🎯 Quick Quiz — Test Yourself!

✏️ Practice Questions

Time

Time (continued)