PW Class 6 Maths Notes Chapter 5: Prime Time

Factors, multiples, prime numbers, and divisibility rules are closely connected, so it can become difficult to remember how each concept works while solving questions. You may also need to apply different divisibility rules or break a number into its prime factors during practice.

PW Class 6 Maths Chapter 5 Notes bring the key definitions, rules, and examples from Prime Time together for easier revision. You can refer to these notes while studying the chapter, before solving exercises, or whenever you need to refresh a particular concept.

What Are Common Factors?

Factors are the numbers that can divide a given number completely. For example, the factors of 6 are 1, 2, 3, and 6 because these are the numbers that divide 6 without a remainder. Example: Common factors of 12 and 18:

• The factors of 12 are 1, 2, 3, 4, 6, and 12.

• The factors of 18 are 1, 2, 3, 6, 9, and 18. 

So, the common factors of 12 and 18 are 1, 2, 3, and 6. These are the numbers that can divide both 12 and 18 without leaving a remainder.

Understanding Common Multiples

A multiple is the result of multiplying a number by any whole number. For example, the multiples of 4 are 4, 8, 12, 16, 20, and so on. Common multiples are the multiples that are shared by two or more numbers. Example: Common multiples of 4 and 6:

• The multiples of 4 are 4, 8, 12, 16, 20, 24, and so on.

• The multiples of 6 are 6, 12, 18, 24, 30, and so on. So, the common multiples of 4 and 6 are 12, 24, 36, and so on. Note: The smallest common multiple of two numbers is called the Least Common Multiple or LCM.

What Are Prime Numbers?

A Prime Number is a number greater than 1 that has only two factors: 1 and the number itself. In other words, a prime number can only be divided by 1 and itself without leaving a remainder.

Understanding Co-prime Numbers

Two numbers are co-prime if their Greatest Common Factor (GCF) or Greatest Common Divisor (GCD) is 1. In other words, co-prime numbers don’t share any factors other than 1. 

Examples: 5 and 9, 8 and 15, 9 and 28, 5 and 14, 12 and 25, 7 and 30, etc

What Is Prime Factorisation?

Prime Factorisation is the process of breaking down a number into a product of its prime factors. Examples:

• Prime Factorisation of 12 is 2 × 2 × 3.

• Prime Factorisation of 18 is 2 × 3 × 3.

Applying Divisibility Tests

Divisibility tests are rules that help you check whether a number can be divided completely by another number. The chapter covers divisibility tests for 2, 3, 4, 5, 6, 8, 9, and 10. 

Download CBSE Class 6 Maths Chapter 5 Notes PDF

When you need to revise Prime Time without going through the complete chapter again, a concise set of notes can help you recall the definitions and rules you have already studied. PW Chapter 5 Notes can be used alongside your textbook and question practice for quick revision.

How Do Physics Wallah Notes Help You Revise Chapter 5?

PW Chapter 5 Notes focus on the specific concepts covered in Prime Time, making them useful when you need to check a rule or revise a calculation method quickly.

• Factors and multiples: Revisit the difference between factors and multiples with examples.

• Prime numbers: Recall the defining property of prime numbers and how they differ from other numbers.

• Co-prime numbers: Check the GCF/GCD condition used to identify co-prime pairs.

• Prime factorisation: Review how a number can be expressed as a product of prime factors.

• Divisibility rules: Keep the tests for 2, 3, 4, 5, 6, 8, 9, and 10 available for quick reference.

• Worked examples: Use the examples in the notes to recall how the concepts are applied while solving questions.

Use PW Class 6 Maths Chapter 5 Notes as a quick reference while revising Prime Time. Reviewing the key rules and examples can help you recall factors, multiples, prime factorisation, and divisibility tests before you move on to NCERT exercises and other practice questions.

Related Resource 

• CBSE Class 6 Maths NCERT Solutions 

• CBSE Class 6 Maths Sample Paper 

• CBSE Class 6 Maths Most Important Questions