102 LearnersLast updated on August 6th, 2025
GCF of 18 and 32
The GCF is the largest number that can divide two or more numbers without leaving any remainder. GCF is used to share items equally, to group or arrange items, and to schedule events. In this topic, we will learn about the GCF of 18 and 32.
What is the GCF of 18 and 32?
The greatest common factor of 18 and 32 is 2. The largest divisor of two or more numbers is called the GCF of the numbers. If two numbers are co-prime, they have no common factors other than 1, so their GCF is 1. The GCF of two numbers cannot be negative because divisors are always positive.
How to find the GCF of 18 and 32?
To find the GCF of 18 and 32, a few methods are described below:
- Listing Factors
- Prime Factorization
- Long Division Method / by Euclidean Algorithm
GCF of 18 and 32 by Using Listing of factors
Steps to find the GCF of 18 and 32 using the listing of factors:
Step 1: Firstly, list the factors of each number:
Factors of 18 = 1, 2, 3, 6, 9, 18.
Factors of 32 = 1, 2, 4, 8, 16, 32.
Step 2: Now, identify the common factors of them.
Common factors of 18 and 32: 1, 2.
Step 3: Choose the largest factor:
The largest factor that both numbers have is 2.
The GCF of 18 and 32 is 2.
GCF of 18 and 32 Using Prime Factorization
To find the GCF of 18 and 32 using the Prime Factorization Method, follow these steps:
Step 1: Find the prime factors of each number:
Prime Factors of 18: 18 = 2 × 3 × 3 = 2 × 3²
Prime Factors of 32: 32 = 2 × 2 × 2 × 2 × 2 = 2⁵
Step 2: Now, identify the common prime factors.
The common prime factor is: 2
Step 3: Multiply the common prime factors.
The Greatest Common Factor of 18 and 32 is 2.
GCF of 18 and 32 Using Division Method or Euclidean Algorithm Method
Find the GCF of 18 and 32 using the division method or Euclidean Algorithm Method. Follow these steps:
Step 1: First, divide the larger number by the smaller number
Here, divide 32 by 18 32 ÷ 18 = 1 (quotient), The remainder is calculated as 32 − (18×1) = 14
The remainder is 14, not zero, so continue the process
Step 2: Now divide the previous divisor (18) by the previous remainder (14)
Divide 18 by 14 18 ÷ 14 = 1 (quotient), remainder = 18 − (14×1) = 4
Step 3: Now divide the previous divisor (14) by the previous remainder (4)
Divide 14 by 4 14 ÷ 4 = 3 (quotient), remainder = 14 − (4×3) = 2
Step 4: Now divide the previous divisor (4) by the previous remainder (2)
Divide 4 by 2 4 ÷ 2 = 2 (quotient), remainder = 4 − (2×2) = 0
The remainder is zero, so the divisor will become the GCF.
The GCF of 18 and 32 is 2.
Common Mistakes and How to Avoid Them in GCF of 18 and 32
Finding GCF of 18 and 32 looks simple, but students often make mistakes while calculating the GCF. Here are some common mistakes to be avoided by students.
Mistake 1
Listing Incorrect Factors
Students may sometimes list incorrect factors.
For example, while listing factors of 18, students may mention 5, which is incorrect. To avoid this, students should carefully divide the number and list the factors correctly.
Mistake 2
Choosing the wrong common factor
Students may sometimes select the smallest common factor instead of the largest one. To avoid this confusion, students should list all the common factors and find the greatest one.
Mistake 3
Forgetting to include 1 as a factor
Sometimes students may forget 1 as a common factor of the numbers. However, it does not affect the GCF, but it indicates an incomplete understanding of the factors. Students should include 1 as a factor.
Mistake 4
Using Multiples instead of factors
Students confuse factors and multiples. In that confusion, sometimes they may write multiples instead of factors. To avoid this confusion, students should know the definitions of multiples and factors clearly.
Mistake 5
Assuming GCF is always an even number
Students may assume that the GCF of two numbers will always be an even number. But it's not true; a GCF can also be an odd number. To avoid this, students should focus on common factors rather than focusing on even and odd numbers.
Greatest Common Factor of 18 and 32 Examples
Problem 1
A baker has 18 chocolate muffins and 32 vanilla muffins. She wants to pack them into boxes with the same number of muffins in each box, with the largest number of items possible in each box. How many muffins will be in each box?
We should find the GCF of 18 and 32.
GCF of 18 and 32 is 2.
There will be 2 muffins in each box.
18 ÷ 2 = 9
32 ÷ 2 = 16
There will be 2 muffins per box, and each box will contain 9 chocolate and 16 vanilla muffins.
Explanation
As the GCF of 18 and 32 is 2, the baker can make 2 muffins per box.
Now divide 18 and 32 by 2.
Each box contains 9 chocolate and 16 vanilla muffins.
Problem 2
A farmer has 18 apple trees and 32 orange trees. He wants to arrange them in rows with the same number of trees in each row, using the largest possible number of trees per row. How many trees will be in each row?
GCF of 18 and 32 is 2.
So each row will have 2 trees.
Explanation
There are 18 apple trees and 32 orange trees.
To find the total number of trees in each row, we should find the GCF of 18 and 32.
There will be 2 trees in each row.
Problem 3
A decorator has 18 meters of red ribbon and 32 meters of blue ribbon. She wants to cut both ribbons into pieces of equal length, using the longest possible length. What should be the length of each piece?
For calculating the longest equal length, we have to calculate the GCF of 18 and 32.
The GCF of 18 and 32 is 2.
The ribbon pieces will be 2 meters long.
Explanation
For calculating the longest length of the ribbon, first, we need to calculate the GCF of 18 and 32, which is 2.
The length of each piece of ribbon will be 2 meters.
Problem 4
A carpenter has two wooden planks, one 18 cm long and the other 32 cm long. He wants to cut them into the longest possible equal pieces, without any wood left over. What should be the length of each piece?
The carpenter needs the longest piece of wood
GCF of 18 and 32 is 2.
The longest length of each piece is 2 cm.
Explanation
To find the longest length of each piece of the two wooden planks, 18 cm and 32 cm, respectively.
We have to find the GCF of 18 and 32, which is 2 cm.
The longest length of each piece is 2 cm.
Problem 5
If the GCF of 18 and ‘a’ is 2, and the LCM is 288. Find ‘a’.
The value of ‘a’ is 32.
Explanation
GCF × LCM = product of the numbers
2 × 288 = 18 × a
576 = 18a
a = 576 ÷ 18 = 32
FAQs on the Greatest Common Factor of 18 and 32
1.What is the LCM of 18 and 32?
2.Is 18 divisible by 2?
3.What will be the GCF of any two prime numbers?
4.What is the prime factorization of 32?
5.Are 18 and 32 prime numbers?
6.How can children in Saudi Arabia use numbers in everyday life to understand GCF of 18 and 32?
7.What are some fun ways kids in Saudi Arabia can practice GCF of 18 and 32 with numbers?
8.What role do numbers and GCF of 18 and 32 play in helping children in Saudi Arabia develop problem-solving skills?
9.How can families in Saudi Arabia create number-rich environments to improve GCF of 18 and 32 skills?
Important Glossaries for GCF of 18 and 32
- Factors: Factors are numbers that divide the target number completely. For example, the factors of 18 are 1, 2, 3, 6, 9, and 18.
- Multiple: Multiples are the products we get by multiplying a given number by another. For example, the multiples of 3 are 3, 6, 9, 12, 15, and so on.
- Prime Factors: These are the factors of a number that are prime numbers and divide the given number completely. For example, the prime factors of 18 are 2 and 3.
- Remainder: The value left after division when the number cannot be divided evenly. For example, when 18 is divided by 5, the remainder is 3 and the quotient is 3.
- LCM: The smallest common multiple of two or more numbers is termed LCM. For example, the LCM of 18 and 32 is 288.
Hiralee Lalitkumar Makwana
About the Author
Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.
Fun Fact
: She loves to read number jokes and games.
