Rivalry2

HTML Diff

1 added 1 removed

Original 2026-01-01

Modified 2026-02-28

1 - <p>115 Learners</p>

1 + <p>120 Learners</p>

2 <p>Last updated on<strong>October 29, 2025</strong></p>

3 <p>The numbers that two or more other numbers share as factors are called common factors. This article discusses the common factors of 3 and 21. We’ll also learn how to use the concept of common factors in our everyday life.</p>

4 <h2>What are the Common Factors of 3 and 21?</h2>

5 <p>The<a>common factors</a>of 3 and 21 are 1 and 3. There are different methods to find the common factors of two or more<a>numbers</a>. Let’s focus on the listing factors method.</p>

6 <h2>How to Find the Common Factors of 3 and 21?</h2>

7 <p>Let’s use the listing<a>factors</a>method here. The first step is to list all the factors of 3 and 21 separately. Once the factors of both numbers are listed, we can compare them and identify the common factors.</p>

8 <p><strong>Step 1:</strong>List all the factors</p>

9 <p>Factors of 3: 1, 3</p>

10 <p>Factors of 21: 1, 3, 7, 21</p>

11 <p><strong>Step 2:</strong>Compare and identify common factors 1 and 3 are the numbers that appear in both lists of factors.</p>

12 <p>Therefore, they are the common factors of 3 and 21.</p>

13 <h2>What are the Methods to Find the Common Factors of 3 and 21?</h2>

14 <p>As mentioned earlier, there are different methods to find the common factors. We’ve already seen the listing factors method, and this section discusses the other commonly used methods.</p>

15 <p><strong>Prime Factorization:</strong>For larger numbers, finding the common factors using the listing factors method can be laborious. Hence, we use the<a>prime factorization</a>method, where we find the prime factorization of each number to identify the common prime factors. We then multiply them to get the<a>greatest common factor</a>(GCF).</p>

16 <p><strong>Venn Diagram:</strong>Students who are good at visualization are encouraged to use this method, as it combines prime factorization and visual thinking. The first step is to prime factor each number and place the factors in a Venn diagram. The overlapping section shows the shared primes; multiply them to get the GCF. Now we can find the factors of the GCF to get all the common factors.</p>

17 <p><strong>Division Ladder Method:</strong>The first step is to find all the<a>prime numbers</a>that can divide the given numbers without leaving any<a>remainder</a>. Once we have all the prime numbers, multiply them to get the GCF. We can then find all factors of the GCF to get the common factors.</p>

18 <h2>Important Glossaries of Common Factors of 3 and 21</h2>

19 <ul><li><strong>Factor -</strong>When a number divides another number without leaving a remainder, it is known as a factor of that number.</li>

20 </ul><ul><li><strong>Greatest Common Factor (GCF) -</strong>The biggest number that exactly divides all given numbers.</li>

21 </ul><ul><li><strong>Prime Factorization -</strong>The method of breaking down a number into the product of prime numbers.</li>

22 </ul><ul><li><strong>Venn Diagram -</strong>A visual method that helps in identifying common factors by overlapping sets.</li>

23 </ul><ul><li><strong>Listing Factors Method -</strong>The method of listing out all factors of all given numbers and comparing them to find the common factors.</li>

24 </ul><p>What Are Numbers? 🔢 | Fun Explanation with 🎯 Real-Life Examples for Kids | ✨BrightCHAMPS Math</p>

25 <p>▶</p>

26 <h2>Hiralee Lalitkumar Makwana</h2>

27 <h3>About the Author</h3>

28 <p>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.</p>

29 <h3>Fun Fact</h3>

30 <p>: She loves to read number jokes and games.</p>