Natural Numbers:
1,2,3,4,5,6,7,8 are called natural numbers. The smallest natural number is 1.
Whole Numbers:
Natural numbers with zero are called whole numbers. 0,1,2,3,4,5,6,7,8 are whole numbers. The smallest whole number is 0.
Even Numbers:
The numbers which are divisible by 2, are called even numbers. 2,4,6,8,10 are all even numbers.
Odd Numbers:
The numbers which are not divisible by 2 are called odd numbers. 1,3,5,7,9 are all odd numbers.
Prime Numbers:
A number which is divisible only by 1 and itself is called Prime Number. It is not divisible by any other numbers. 2,3,5,7,11,13,17,23,31,37,41,43,47, are all prime numbers between 1 to 50. 2 in the only even prime number.
Composite Numbers:
All numbers greater than 1 which are not prime numbers are called composite numbers. 4,6,8,9,10,12,14,15,16… are composite numbers.