CBSE Class–10 Mathematics Revision Notes CHAPTER 01 REAL NUMBERS Natural numbers : Counting numbers are called Natural numbers. These numbers are denoted by N = {1, 2, 3, .........} Whole numbers : The collection of natural numbers along with 0 is the collection of Whole number and is denoted by W. Integers : The collection of natural numbers, their negatives along with the number zero are called Integers. This collection is denoted by Z. Rational number : The numbers, which are obtained by dividing two integers, are called Rational numbers.  Division by zero is not defined . Coprime : If HCF of two numbers is 1, then the two numbers area called relatively prime or coprime. 1.  Euclid’s division lemma : For given positive integers ‘a’ and ‘b’ there exist unique whole numbers ‘q’ and ‘r’ satisfying the relation  a  = bq  + r ,   0 ⩽ r  < b . a  = bq  + r ,   0 ⩽ r  < b . . Theorem: If  a a  and  b b  ...