IBPS CWE PO STUDY MATERIAL QUANTITATIVE APTITUDE NUMBER SYSTEM
IMPORTANT FACTS AND FORMULAE 1.Natural Numbers : Counting numbers 1, 2, 3, 4, 5,..... are called natural numbers. 2 . Whole Numbers : All counting numbers together with zero form the set of whole numbers . Thus, (i) 0 is the only whole number which is not a natural number. (ii) Every natural number is a whole number. 3.Even Numbers : A number divisible by 2 is called an even number, e.g., 2, 4, 6, 8, 10, etc. 4. Odd Numbers : A number not divisible by 2 is called an odd number. e.g., 1, 3, 5, 7, 9, 11, etc. 5. Prime Numbers : A number greater than 1 is called a prime number, if it has exactly two factors, namely 1 and the number itself. Prime numbers upto 100 are : 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43,47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97. 7.Composite Numbers :...