To find the Lowest Common Multiple (LCM) using prime factorization, follow these steps:
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Find the Prime Factorization: Determine the prime factorization of each number you want to find the LCM for. This means breaking down each number into a product of its prime factors.
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List Prime Factors with Highest Powers: For each prime factor that appears in any of the factorizations, list it with the highest power to which it appears in any of the individual prime factorizations.
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Multiply: Multiply all the prime factors (with their highest powers) listed in the previous step. The result is the LCM.
Here's an example to illustrate the process:
Example: Find the LCM of 12 and 18.
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Prime Factorization:
- 12 = 2 x 2 x 3 = 22 x 3
- 18 = 2 x 3 x 3 = 2 x 32
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List Prime Factors with Highest Powers:
- The prime factors are 2 and 3.
- The highest power of 2 is 22.
- The highest power of 3 is 32.
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Multiply:
- LCM = 22 x 32 = 4 x 9 = 36
Therefore, the LCM of 12 and 18 is 36.
In essence: Prime factorization allows you to identify all the necessary prime components to construct a multiple common to all the original numbers, ensuring you choose the lowest such multiple by considering only the highest required power of each prime.