Number System
Natural numbers {N}
The counting numbers {1, 2, 3, 4, 5…} are called natural numbers;
Whole numbers
Natural numbers including 0 {0, 1, 2, 3, 4, 5…} are also called whole numbers.
Negative numbers are not considered “whole numbers.”
Integers {Z}
Positive and negative counting numbers, as well as zero: {…, −3, −2, −1, 0, 1, 2, 3, …} are called integers.
Even Number
The Numbers that are divisible by 2 are known as Even Numbers.
Even Numbers – 2,4,6,8,10,12,14,16,18 and so on.
Odd Numbers
The Numbers which are not divisible by 2 are known as Odd Numbers. In other words, the odd numbers are those numbers which are not even.
Odd Numbers – 1, 3, 5, 7, 9, 11, 13, 15, 17 and so on.
Prime Number
The numbers that are divisible by one and itself and not divisible by any other number.
Prime Numbers are: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 and so on.
Rational Number
Any number which can be expressed in the form of, where a and b both are integers and, b is not equal to 0 is a rational number. Ex – 3/5, 2/6. 9/8.
Composite Numbers
A composite number is a whole number (greater than 1) that is not prime.
Composite numbers C= (4,6,8,9 ……..,etc.)
Number System
- Every number, which is either rational or irrational is called a real number.
- Each natural number is a real number.
- Each whole number is a real number.
- Each integer is a real number.
- Each rational number is a real number.
- Each irrational number is a real number, etc.
