What is the GCF of 3 and 18

what is the GCF of 3 and 18

The Correct Answer and Explanation is:

The Greatest Common Factor (GCF) of 3 and 18 is 3.


Explanation:

To find the GCF of two numbers means to determine the largest number that divides both numbers exactly, with no remainder.

Step 1: Understand the definition of GCF

The GCF (Greatest Common Factor) is the greatest number that evenly divides two or more numbers. This number must be a factor of both original numbers.

Step 2: List the factors of each number

  • Factors of 3:
    A factor is a number that divides evenly into another number.
    The factors of 3 are: 1, 3
  • Factors of 18:
    The numbers that divide 18 without a remainder are:
    1, 2, 3, 6, 9, 18

Step 3: Identify common factors

Now, compare the factors of 3 and 18:

  • Common factors of 3 and 18: 1, 3

Step 4: Choose the greatest common factor

From the list above, the largest factor that both numbers share is 3.
So, the GCF of 3 and 18 is 3.


Why is the GCF important?

The GCF is used in many areas of mathematics, such as:

  • Reducing fractions: To simplify a fraction, divide both the numerator and denominator by their GCF.
  • Factoring expressions: In algebra, factoring out the GCF makes expressions easier to work with.
  • Problem-solving: The GCF helps solve problems involving ratios, division of items into equal groups, and more.

Shortcut Method: Prime Factorization

  1. Prime factorization of 3: 3
  2. Prime factorization of 18: 2 × 3 × 3

The only prime factor they both share is 3. So, the GCF is 3.


Final Answer:

The GCF of 3 and 18 is 3.

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