## NUMBER  SYSTEM

NATURAL NUMBERS
The counting numbers are 1,2,3,4,5,6,.... are called natural numbers. The set of natural numbers is denoted by N.
Thus, N={1,2,3,4,5,6,....}
WHOLE NUMBERS
The set of natural numbers along with 0 represents whole numbers. The set of whole numbers is denoted by W.
Thus, W={0,1,2,3,4,5,.......}

INTEGERS
The set of whole numbers along with the negatives of natural numbers represents integers. The set of integers is denoted by I or Z.
Thus, I or Z={......,-3,-2,-1,0,1,2,3,......}
RATIONAL NUMBERS
The numbers in the form p/q, where p and q are both integers, q not equal to 0 and p and q have no common factors except 1 i.e. p and q are co-prime, are called rational numbers. The set of rational numbers is denoted by Q.
Thus, Q={p/q; p ,q belongs to Z , q not equal to 0}
IRRATIONAL NUMBERS
The numbers which cannot be expressed in the form p/q , where p and q are both integers and q not equal to 0, are called irrational numbers.
REAL NUMBERS
All rational and irrational numbers together called real numbers. The set of real numbers is denoted by R.