Fraser Institute

1.     Natural numbers N = {1, 2, 3, 4...........+∞}  2.     Integers Z = {-∞........,-3, -2, -1, 0, 1, 2, 3, 4..........+∞} 3.     Positive integers Z +  = {1, 2, 3, 4, ..........+∞} 4.     Negative integers Z -  = {-∞,..........-3, -2, -1} 5.     Non - negative integers or Whole numbers = {0, 1, 2, 3, 4, ..........+∞} 6.     Non - positive integers ={-∞,..........-3, -2, -1,0} 7.     Rational numbers Q = all numbers of the form p/q, where p an q are integers and b ≠ 0 are called rational numbers and their set is denoted by Q. Q=p/q such that a, b ε Z and b≠0 and HCF of a,b is 1. ·          Every integer is a rational number as it could be written as Q=p/q ·          All recurring decimals are rational numbers e.g. Q= 1/3= 0.333333. 8.     Irrational numbers Q c = those values which neither terminate nor could be expressed as recurring decimals are called irrational numbers i.e. it cannot be expressed as p/q form, and are denoted by Q c e.g. sqrt (2) = 1.41421