If you’re grappling with the concept of the greatest common factor (GCF), or the highest common factor, of 48 and 72, you’re not alone. The GCF represents the largest number that evenly divides into both numbers without leaving a remainder. Understanding this mathematical operation is crucial for problem-solving related to fractions, least common multiples, and other arithmetic operations.

The GCF of 48 and 72 can be calculated using a variety of methods, including prime factorization, factor trees, or the Euclidean algorithm. Prime factorization involves breaking down each number into its prime factors, which are numbers divisible only by themselves and 1. Factor trees, on the other hand, depict the factors of each number in a branching diagram. Finally, the Euclidean algorithm repeatedly subtracts the smaller number from the larger until the remainder is 0, with the final divisor being the GCF.

Regardless of the method employed, the GCF of 48 and 72 is 24. This means that 24 is the greatest number that divides into both 48 and 72 without leaving a remainder. This concept is significant in mathematical operations because it helps us simplify fractions, find least common multiples, and solve other types of problems.

Prime Factorization


Prime factorization is a process of breaking down a given number into a set of prime numbers multiplied together. Prime numbers are numbers that have exactly two distinct factors: 1 and the number itself.


  1. Find the smallest prime factor of the number and divide the number by that factor.
  2. Repeat step 1 until you are left with a prime number.
  3. Write the prime factors as a multiplication expression.


Prime factorization of 48: 2 × 2 × 2 × 2 × 3

Prime factorization of 72: 2 × 2 × 2 × 3 × 3

Factor Trees


A factor tree is a diagram that shows all the factors of a number. It starts with the number at the top and branches out into smaller factors.


  1. Start with the number at the top of the tree.
  2. Find two factors of the number and write them below the number, connected by a line.
  3. Repeat step 2 for each of the new factors until you reach the prime factors.


Factor tree of 48:

       /  \
      24   2
     / \   / \
    12  12 1   2
   / \   / \
  6   2 6   1
 / \   /
3   2 3

Factor tree of 72:

      /  \
     36   2
    / \   / \
   18  18 1   2
   / \   / \
  9   9 6   1
 / \   /
3   3 3

Euclidean Algorithm


The Euclidean algorithm is a method for finding the greatest common factor (GCF) of two numbers. It is based on the fact that the GCF of two numbers is the same as the GCF of the larger number and the remainder when the larger number is divided by the smaller number.


  1. Divide the larger number by the smaller number.
  2. Find the remainder.
  3. Repeat steps 1 and 2 until the remainder is 0.
  4. The last non-zero remainder is the GCF of the two numbers.


GCF of 48 and 72 using the Euclidean algorithm:

72 ÷ 48 = 1 remainder 24
48 ÷ 24 = 2 remainder 0

Therefore, the GCF of 48 and 72 is 24.

Applications of GCF

Simplifying Fractions

The GCF is used to simplify fractions by dividing both the numerator and denominator by their GCF. This results in a fraction that is equivalent to the original fraction, but has a smaller numerator and denominator.

Finding Least Common Multiples (LCM)

The LCM of two numbers is the smallest number that is divisible by both numbers. The LCM can be found by multiplying the two numbers and dividing by their GCF.

Solving Other Types of Problems

The GCF is also used to solve other types of problems, such as finding the number of objects that can be divided equally into two or more groups, and finding the area of the largest square that can be cut from a rectangular piece of paper.


Understanding the concept of the GCF is essential for a variety of mathematical operations. By using methods such as prime factorization, factor trees, or the Euclidean algorithm, we can efficiently calculate the GCF of any two numbers. This knowledge plays a crucial role in simplifying fractions, finding LCMs, and solving various mathematical problems.



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