Class 6 Mathematics

Chapter 3: Playing with Numbers

STAGE 0: Foundation

Numbers have special properties 😊

We can break numbers, check patterns, and test divisibility.

In this chapter, we learn:

Factors and multiples
Prime and composite numbers
Divisibility rules
HCF and LCM (basic idea)

STAGE 1: Concepts Explained

Factors

A factor is a number that divides another number exactly.

Example:

Factors of 12 are 1, 2, 3, 4, 6, 12

Multiples

Multiples are numbers obtained by multiplying a number.

Example:

Multiples of 5 are 5, 10, 15, 20, ...

Prime Numbers

Prime numbers have only two factors: 1 and itself.

Examples: 2, 3, 5, 7, 11

Composite Numbers

Composite numbers have more than two factors.

Examples: 4, 6, 8, 9, 10

Divisibility Rules

Divisible by 2 → last digit is even
Divisible by 3 → sum of digits divisible by 3
Divisible by 5 → last digit is 0 or 5
Divisible by 10 → last digit is 0

HCF (Highest Common Factor)

HCF is the greatest common factor of two numbers.

Example:

HCF of 12 and 18 = 6

LCM (Least Common Multiple)

LCM is the smallest common multiple of two numbers.

Example:

LCM of 4 and 6 = 12

STAGE 2: Solved Examples

Example 1:
Find the factors of 15.

Solution:
Factors of 15 are 1, 3, 5, 15.

Example 2:
Is 29 a prime number?

Solution:
29 has only two factors (1 and 29).
So, it is a prime number.

Example 3:
Find the LCM of 3 and 4.

Solution:
LCM of 3 and 4 = 12.

STAGE 3: Practice Questions

1. Write all factors of 24.
2. Write first five multiples of 6.
3. Is 21 a prime or composite number?
4. Check whether 345 is divisible by 3.
5. Find the HCF of 8 and 16.

STAGE 4: Quick Revision

Factors divide numbers exactly
Multiples are products
Prime numbers have two factors
Composite numbers have more than two factors
HCF is greatest common factor
LCM is least common multiple

Shaktimatha CBSE Learning
Class 6 Mathematics – Learn Without Fear

Playing with numbers helps us understand Maths better.

Class 6 Mathematics – Complete NCERT Library

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