GCF of 1 and 3
2026-02-21 20:28 Diff
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Last updated on September 24, 2025

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 schedule events. In this topic, we will learn about the GCF of 1 and 3.

What is the GCF of 1 and 3?

The greatest common factor of 1 and 3 is 1. 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 1 and 3?

To find the GCF of 1 and 3, a few methods are described below 

  • Listing Factors
     
  • Prime Factorization
     
  • Long Division Method / by Euclidean Algorithm

GCF of 1 and 3 by Using Listing of Factors

Steps to find the GCF of 1 and 3 using the listing of factors:

Step 1: Firstly, list the factors of each number

Factors of 1 = 1.

Factors of 3 = 1, 3.

Step 2: Now, identify the common factors of them Common factor of 1 and 3: 1.

Step 3: Choose the largest factor The largest factor that both numbers have is 1.

The GCF of 1 and 3 is 1.

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GCF of 1 and 3 Using Prime Factorization

To find the GCF of 1 and 3 using the Prime Factorization method, follow these steps:

Step 1: Find the prime factors of each number

Prime Factors of 1: 1 (since 1 is neither prime nor composite, it has no prime factors).

Prime Factors of 3: 3.

Step 2: Now, identify the common prime factors There are no common prime factors.

Step 3: Since there are no common prime factors, the GCF is 1.

GCF of 1 and 3 Using Division Method or Euclidean Algorithm Method

Find the GCF of 1 and 3 using the division method or Euclidean Algorithm Method. Follow these steps:

Step 1: First, divide the larger number by the smaller number

Here, divide 3 by 1 3 ÷ 1 = 3 (quotient),

The remainder is calculated as 3 − (1×3) = 0

The remainder is zero, so the divisor will become the GCF.

The GCF of 1 and 3 is 1.

Common Mistakes and How to Avoid Them in GCF of 1 and 3

Finding the GCF of 1 and 3 looks simple, but students often make mistakes while calculating the GCF. Here are some common mistakes to be avoided by the students.

Problem 1

A gardener has 1 rose and 3 tulips. She wants to create bouquets with the largest number of flowers possible in each. How many flowers will be in each bouquet?

Okay, lets begin

We should find the GCF of 1 and 3.

The GCF of 1 and 3 is 1.

There will be 1 bouquet, and each bouquet has 1 rose and 3 tulips.

Explanation

As the GCF of 1 and 3 is 1, the gardener can make 1 bouquet.

Each bouquet gets 1 rose and 3 tulips.

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Problem 2

A teacher has 1 book and 3 notebooks. She wants to place them in stacks with the same number of items in each stack, using the largest possible number of items per stack. How many items will be in each stack?

Okay, lets begin

The GCF of 1 and 3 is 1.

So each stack will have 1 item.

Explanation

There is 1 book and 3 notebooks.

To find the total number of items in each stack, we should find the GCF of 1 and 3.

There will be 1 item in each stack.

Well explained 👍

Problem 3

A technician has 1 meter of red cable and 3 meters of blue cable. She wants to cut both cables into pieces of equal length, using the longest possible length. What should be the length of each piece?

Okay, lets begin

For calculating the longest equal length, we have to calculate the GCF of 1 and 3.

The GCF of 1 and 3 is 1.

The cable is 1 meter long.

Explanation

For calculating the longest length of the cable, first, we need to calculate the GCF of 1 and 3, which is 1.

The length of each piece of the cable will be 1 meter.

Well explained 👍

Problem 4

A carpenter has two wooden planks, one 1 cm long and the other 3 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?

Okay, lets begin

The carpenter needs the longest piece of wood.

The GCF of 1 and 3 is 1.

The longest length of each piece is 1 cm.

Explanation

To find the longest length of each piece of the two wooden planks, 1 cm and 3 cm, respectively, we have to find the GCF of 1 and 3, which is 1 cm.

The longest length of each piece is 1 cm.

Well explained 👍

Problem 5

If the GCF of 1 and ‘a’ is 1, and the LCM is 3. Find ‘a’.

Okay, lets begin

The value of ‘a’ is 3.

Explanation

GCF x LCM = product of the numbers

1 × 3 = 1 × a

3 = a

Well explained 👍

FAQs on the Greatest Common Factor of 1 and 3

1.What is the LCM of 1 and 3?

2.Is 1 divisible by any number other than itself?

No, 1 is only divisible by itself.

3.What will be the GCF of any two prime numbers?

The common factor of prime numbers is 1 and the number itself. Since 1 is the only common factor of any two prime numbers, it is said to be the GCF of any two prime numbers.

4.What is the prime factorization of 3?

The prime factorization of 3 is 3 itself, as it is a prime number.

5.Are 1 and 3 prime numbers?

1 is not a prime number because it has only one factor, which is itself. 3 is a prime number because it has exactly two distinct positive divisors: 1 and 3.

Important Glossaries for GCF of 1 and 3

  • Factors: Factors are numbers that divide the target number completely. For example, the factors of 3 are 1 and 3.
  • 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, 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 factor of 3 is 3.
  • Remainder: The value left after division when the number cannot be divided evenly. For example, when 3 is divided by 2, the remainder is 1.
  • GCF: The largest factor that commonly divides two or more numbers. For example, the GCF of 1 and 3 is 1, as it is their largest common factor that divides the numbers completely.

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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.