NCERT Class 5 Mathematics Math-Mela: Chapter 12 — 12
This chapter, "Racing Seconds," from NCERT Class 5 Mathematics Math-Mela, focuses on understanding and calculating time intervals. It introduces concepts like starting and finishing times, duration, and elapsed time. Students will practice finding the time difference between given periods, including calculations involving hours and minutes. The chapter also covers converting between 12-hour and 24-hour time formats and comparing durations. Through examples like Raghav's yoga practice and a school race, students learn to apply these time-related skills in practical scenarios, enhancing their mathematical understanding of time measurement.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 5 |
| Subject | Mathematics |
| Book | Math-Mela |
| Chapter | Chapter 12 — 12 |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 1 minute |
| Word count | 163 |
Learning outcomes
- Calculate the duration of an activity.
- Find the time elapsed between two given times.
- Convert time between 12-hour and 24-hour formats.
- Compare time taken by different individuals for tasks.
- Solve word problems involving time calculations.
Vocabulary
| Word | Meaning |
|---|---|
| Practising | Engaging in an activity repeatedly to improve skill. |
| Elapsed | Having passed or gone by (referring to time). |
| Minutes | A unit of time equal to 60 seconds. |
| Hours | A unit of time equal to 60 minutes. |
| Format | The way in which something is arranged or presented. |
| Participating | Taking part in an event or activity. |
| Duration | The length of time something continues or lasts. |
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Practice questions
- If Raghav started yoga at 6:15 a.m. and finished at 6:40 a.m., how long did he practice? Answer: 25 minutes
- Find the time elapsed between 02:30 p.m. and 03:15 p.m. Answer: 45 minutes
- Convert 07:45 a.m. to 24-hour format. Answer: 07:45 hours
- Convert 15:30 hours to 12-hour format. Answer: 03:30 p.m.
- Rani took 2 hours 10 minutes to paint. Ritu took 1 hour 35 minutes. Who took longer? Answer: Rani
Frequently asked questions
What is the main focus of the 'Racing Seconds' chapter?
The chapter focuses on understanding and calculating time intervals, elapsed time, and time conversions.
How do you calculate the time spent practicing yoga in the chapter?
You calculate the difference between the finishing time and the starting time to find the duration.
What are the two time formats discussed in the chapter?
The chapter discusses the 12-hour format (a.m./p.m.) and the 24-hour format.
What does 'elapsed time' mean?
Elapsed time is the total amount of time that has passed between a start time and an end time.
How can you compare the time taken by different children to paint a picture?
By comparing the durations (time taken) for each child, you can determine who took the longest or least time.
What kind of practical applications of time calculation are shown?
Practical applications include Raghav's yoga practice and a school walking race.
Related resources
Important topics
Topics covered
NCERT Class 5 Mathematics — Math-Mela — Chapter 12 — 12. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.