# Session 31: The Least Common Multiple (LCM)

<div align="left" dir="ltr" id="bkmrk-session-title-the-mu"><table style="width: 117.5%; height: 485px;"><colgroup><col style="width: 39.905363%;" width="199"></col><col style="width: 59.936909%;" width="434"></col></colgroup><tbody><tr style="height: 36px;"><td class="align-center" style="height: 36px;">**Session Title**

</td><td class="align-center" style="height: 36px;">**The Multiple Mysteries**

  
</td></tr><tr style="height: 173px;"><td style="height: 173px;">Objective

</td><td style="height: 173px;">By the end of this session, students will be able to:

  
1\. Understand the concept of the Least Common Multiple (LCM)

  
  
2\. Find the LCM of the given numbers using different methods.

  
  
3\. Develop problem-solving and teamwork skills

  
</td></tr><tr style="height: 109px;"><td style="height: 109px;">Topics

</td><td style="height: 109px;">The Least Common Multiple (LCM) is the smallest multiple that two or more numbers share.

  
It is useful in real-life applications, such as scheduling events, solving fraction problems, and understanding patterns.

  
</td></tr><tr style="height: 61px;"><td style="height: 61px;">Material Required

</td><td style="height: 61px;">Board &amp; Chalk

Before starting the class, draw a number grid ( up to 50 ) on the floor

  
</td></tr><tr style="height: 77px;"><td style="height: 77px;">Methodology

</td><td style="height: 77px;">Activity-based Learning: Physical activity and group work.

  
Experiential Learning: Relating LCM to real-life situations.

  
</td></tr><tr style="height: 29px;"><td style="height: 29px;">Session Duration

</td><td style="height: 29px;"> 90 Minutes

</td></tr></tbody></table>

</div>### Introduction Activity(10 Minutes) 

**Pass pass**

In "Pass Pass," children form a circle. Choose any number, for example 5. Then each child starts counting from one. When they reach 5 or multiples of five, they have to say pass. If they don't say pass, that child is out. The game continues until only one child remains.(NB: Change the number after each round)

### Main Activity(70 minutes)

**Tell a short story:- ( 20 minutes )**

Two friends, Arya and Rahul, love visiting a park. Arya visits every 3 days, and Rahul visits every 4 days. If both visit the park today, when will they meet again?

Ask students to think and predict: “Will they meet again in a week? In 10 days?”

Guide them to count the days until both are at the park together (on the 12th day).

Explain that the Least Common Multiple (LCM) of 3 and 4 is 12—the smallest number that both 3 and 4 can divide into evenly.

**Game Time ( 25 minutes )**

1. Draw a number grid on the floor (1–50)
2. Call out two numbers (e.g., 4 and 6)
3. Students take turns hopping on the multiples (4, 8, 12… and 6, 12, 18…)
4. The first common number they step on is the LCM ( NB: Repeat the activity with different number )

**Time to solve ( 20 Minutes)**

Give simple examples: ( Divide students into small groups)

- LCM of 2 and 5

→ Multiples: (2, 4, 6, 8, 10, 12…) and (5, 10, 15…) → LCM is 10.

- LCM of 6 and 8

→ Multiples: (6, 12, 18, 24…) and (8, 16, 24…) → LCM is 24.

- A bell rings every 6 minutes, and another bell rings every 8 minutes. After how many minutes will both bells ring together?
- A school organizes a sports day every 5 years, and a cultural fest every 7 years. How many years later will both events happen together again?

### Review Questions(5 minutes)

Ask: What strategies helped you solve the problems quickly?

Encourage peer teaching—students explain their solutions to classmates.

### Follow up Task (10minutes)

**Home work**

1.Two farmers plant crops—one plants every 9 days, and the other every 12 days. In how many days will they plant on the same day again?

2.Two buses leave a station at the same time—one after 12 minutes, the other after 15 minutes. When will they leave together again?

### Expected Learning Outcome:

**Knowledge building-**

- Concept of LCM
- Method to find LCM

**Skill Building-**

- Logical thinking
- Strengthens speed and accuracy
- Team work