Lowest Common Multiple

Name:

Date:

Mathematical symbols and numbers illustration

📚 Part 1: Finding LCM by Listing Multiples

1. Find the LCM of 4 and 6 by listing the first few multiples of each number.

Multiples of 4: _____, _____, _____, _____, _____, _____

Multiples of 6: _____, _____, _____, _____, _____, _____

LCM of 4 and 6 = _____

2. Find the LCM of 8 and 12.

LCM = _____

3. Which of the following is the LCM of 5 and 15?

4. Find the LCM of 9 and 15.

LCM = _____

🔢 Part 2: Finding LCM using Prime Factorisation

5. Complete the prime factorisation and find the LCM of 18 and 24.

18 = 2 × _____ × _____

24 = 2³ × _____

LCM = highest power of each prime = _____

6. Find the LCM of 20 and 30 using prime factorisation. Show your working.

LCM = _____

7. Which method would be more efficient for finding the LCM of 84 and 126?

Listing multiples

Prime factorisation

Explain your choice: _________________________________

🌟 Part 3: Real-Life Applications

8. Two buses leave the station at the same time. Bus A returns every 12 minutes and Bus B returns every 18 minutes. After how many minutes will they both arrive at the station together again?

Answer: _____ minutes

9. Sarah exercises every 4 days and Tom exercises every 6 days. If they both exercised today, in how many days will they exercise together again?

10. A factory produces widgets in batches. Machine X completes a batch every 15 minutes, and Machine Y completes a batch every 20 minutes. If both machines start together, when will they both finish a batch at the same time again?

Answer: _____ minutes