Prime factorization is the process of writing a number as a product of prime numbers only.
In other words:
You break a number down until all the factors are prime numbers.
Why do we use prime factorization?
Prime factorization helps us:
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find common factors
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find LCM (Least Common Multiple) and GCF (Greatest Common Factor)
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simplify fractions
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understand the structure of numbers
Example 1: Prime factorization of 24
Step-by-step:
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Start with the smallest prime number, 2
24 ÷ 2 = 12 -
Divide again by 2
12 ÷ 2 = 6 -
Divide again by 2
6 ÷ 2 = 3 -
3 is a prime number → stop
So:
24=2×2×2×3
Using exponents:
24 = 2^3 × 3
Example 2: Prime factorization of 18
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18 ÷ 2 = 9
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9 ÷ 3 = 3
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3 ÷ 3 = 1
18 = 2 × 3 × 3 = 2 × 3^2
Factor Tree Method 🌳
A factor tree is a visual way to find prime factorization.
Example: 36
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36 → 4 × 9
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4 → 2 × 2
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9 → 3 × 3
So:
36 = 2^2 × 3^2
Important rules to remember
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Only prime numbers appear in the final answer
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You can start with any factor, but using the smallest prime makes it easier
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The process ends when all factors are prime
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1 is never included in prime factorization