Basic Concept Of Math's

A) Natural Numbers : Counting numbers are called natural numbers .



For Ex. 1,2,3,4,5,6,7,......& so on are all natural numbers .


B) Whole Numbers : All counting numbers and 0 form the set of whole numbers .



For Ex. ,1,2,3,4,5,6,7,.....& s on are all whole numbers .



Clearly , every natural number is whole number and 0 is a whole number which is



not a natural number .



C) Integers : All counting numbers ,zero and negatives of counting numbers form



the set of integers .



For Ex. ...........-4, -3, -2,- 1, 0, 1, 2, 3, 4, 5,............. & so on are all integers .



Set of positive integers = { 1, 3, 4, 5, 6, 7,.......}



Set f negative integers = { -1,-2,-,-4,-5,-6,-7,...}



Set of all negative integers = { 0, 1, 2, 3, 4, 5, 6, 7, ........}



D) Even And Odd Numbers : -



Even Numbers : A counting number divisible by 2 is called an even number .



For Ex. 2, 4, 6, 8, 10,....& so on are all even numbers .



Odd Numbers: A counting number not divisible by 2 is called odd number .



For Ex. 1, 3, 5, 7, 9, 11,......& so on



E) Prime Numbers : A counting number is called a prime number if it has exactly



two factors , namely itself and 1 .



For Ex. 3, 5, 7, 11, 13, 1 , 19, 23, 29, 31, 37,........& so on



F) Composite Numbers : The natural numbers which are not prime , are called



composite numbers .



G) Co Primes : Two natural numbers a and b are said to be co-prime if their HCF is 1



For Ex. (2,3),(4,5),(7,9),8,11) & so on are airs of co-primes *