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What is the prime factorization of 18?

User Rahul Tank
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1 Answer

14 votes
14 votes

Answer:

2 x 3 x 3

Explanation:

Prime Factorization is finding which prime numbers multiply together to make the original number.

Prime numbers are whole numbers greater than 1 that cannot be made by multiplying other whole numbers: 2, 3, 5, 7, 11, 13, 17, 19 ... etc.

Factors are the numbers you multiply together to get another number.

To find the prime factors of 18:

Start with dividing the number by the first prime number, 2.

So can 18 be divided by 2? Yes: 18 ÷ 2 = 9 ⇒ So 2 is a factor.

However, 9 is not prime number. Can 9 be divided by 2 and give us a whole number? No, as 9 ÷ 2 = 4.5 and 4.5 is not a whole number.

So let's try dividing 9 by the next prime number, 3: 9 ÷ 3 = 3.

We can now stop as we divided by the prime number 3 AND the result is a prime number.

Therefore, the prime factorization of 18 = 2 x 3 x 3

As two of the factors are the same (3) , we can also write this using exponents: 18 = 2 x 3²

User Maxime Lorant
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