How do you find the LCM of 7 and 9?

To find the Least Common Multiple (LCM) of 7 and 9, you can use a few different methods. Here’s a simple approach using the prime factorization method:

Step 1: Prime Factorization

First, identify the prime factors of each number:

• 7: It is a prime number, so its only factor is 7.
• 9: The prime factorization of 9 is 3 × 3 (or 3²).

Step 2: Identify Unique Factors

Next, list all the unique prime factors:

• From 7: 7
• From 9: 3

Step 3: Multiply the Highest Powers

Now, multiply the highest powers of each prime factor:

• 7¹ (from 7)
• 3² (from 9)

So, the LCM is:

LCM = 7¹ × 3² = 7 × 9 = 63

Final Result

The LCM of 7 and 9 is 63.