Different Types of Numbers - 6th class

Different Types of Numbers - 6th class

Even Numbers: All multiples of 2 are called even numbers. Hence, all even numbers are divisible by 2. Thus 2,4,6,8, etc. are all even numbers. The whole number 0 is also even, since 0 ÷ 2 = 0.

Odd Numbers: Numbers which are not multiples of 2 are called odd numbers. Hence, odd numbers are not divisible by 2. It follows that the numbers which are not even are odd.For example, 1, 3, 5, 7........ are all odd numbers.

Prime Numbers: Numbers which have only 2 factors, 1 and the numbers itself, are called prime numbers. Hence, the prime numbers are divisible by 1 and the number itself and by no  other number. Foe example, 2, 3, 5, 7, 11, 13, 17.......... etc. are prime numbers.

Composite Numbers: Numbers which have more than 2 factors are called composite numbers. Hence, the composite numbers are divisible by more than 2 numbers. For example, 4, 6, 8, 9, 10, 12, etc. are called composite numbers. Since each of these numbers has more than 2 factors.

Unique number: 1 is neither a prime number nor a composite number. It is called a unique number.

Co - prime numbers (or Co -primes): Two numbers are said to be co-primes, if they do not have a common factor other than 1.For example, (2, 3), (2, 5), (3, 4), (3, 5), (4, 9), (15, 16), (27, 28), etc. are pairs of co-primes.It is not necessary that two co-prime numbers should be both prime numbers.

Twin primes: Two prime numbers which have a difference of 2 are called twin primes.For example, (3, 5), (5, 7), (11, 13), (17, 19), (29, 31), etc. are pairs of twin primes.

Perfect number: If the sum of all the factors of a number is twice this number, then this number is called a perfect number.For example, the factors of 6 are 1, 2, 3 and 6 and 1 + 2 + 3 + 6=12=2 * 6.Hence, 6 is a perfect number.

Prime triplet: A collection of three successive prime numbers differing by 2 is called a prime triplet.The only prime triplet is (3, 5, 7).