# NCERT Solutions for Class 6 Math Chapter 3 :Playing With Numbers This chapter introduces the students to the concepts of factor, multiple, prime number, composite numbers, co-prime numbers, rules of divisibility, The Highest Common Factor (HCF) and The Lowest Common Multiple (LCM). A factor of a number is an exact divisor of that number. The number other than 1, with only factors namely 1 and the number itself is a prime number. Numbers that have more than two factors are called composite numbers. Two numbers with only 1 as a common factor are called co-prime numbers. Rules of divisibility help in knowing if a number is divisible by looking at a number, by small numbers 2, 3, 4, 5, 8, 9, and 11. The topics mentioned above are interrelated. One topic leads to another and thus builds the ability to co-relate in the students. This chapter also lays the groundwork for the further complex topics which are introduced in the subsequent chapters in class 6. This chapter works on the student’s multiplication skills which they learnt in the previous classes. Good command on tables helps in arriving at answers quickly and correctly. The topics that are covered in this chapter lay the ground for a better understanding of fractions which will be taught in class 6 in subsequent chapters. This chapter deals with the following concepts:

• Factor
• Multiple
• Prime number
• Perfect number
• Composite numbers
• Co-prime numbers
• The Highest Common Factor (HCF)
• The Lowest Common Multiple (LCM)