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 couple of methods. Here’s a simple approach:

Method 1: Listing Multiples

Start by listing the multiples of each number:

• Multiples of 7: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, ...
• Multiples of 9: 9, 18, 27, 36, 45, 54, 63, 72, ...

Next, look for the smallest multiple that appears in both lists. In this case, the first common multiple is 63.

Method 2: Using Prime Factorization

Another way to find the LCM is through prime factorization:

• 7 is a prime number: 7
• 9 can be factored into: 3 x 3 (or 3²)

Now, take the highest power of each prime number:

• From 7: 7¹
• From 9: 3²

Multiply these together to find the LCM:

LCM = 7¹ × 3² = 7 × 9 = 63

Final Result

Thus, the LCM of 7 and 9 is 63.