Grade 5 : Various Types of Numbers
In various types of numbers we will learn about even numbers, odd numbers, prime numbers, composite numbers, co-prime numbers and twin prime numbers along with the example:
Even Numbers
A whole number exactly divisible by 2 is called even numbers.
For example:
2, 4, 6, 8, 10, 12, 14, 16……………………..are even number. Or a number having 0, 2, 4, 6, 8 at its units place is called an even number.
246, 1894, 5468, 100 are even number.
Any two even numbers which differ from one another by 2 are called consecutive even number.
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Odd Numbers
A whole number which is not exactly divisible by 2 is called an odd number.
For example:
3, 5, 7, 9, 11, 13, 15, are odd number.
Or a number having 1, 3, 5, 7 and 9 at its units place is called an odd number.
Prime Numbers
have only two factors namely 1 and the number itself are called prime numbers.
For example:
2, 3, 5, 7, 11, 19, 37 etc are prime numbers.
Composite Numbers
Numbers having more than two factors are called as composite numbers.
For example:
4, 6, 8, 10 etc are composite numbers.
Notes:
(a) 1 is neither prime nor composite.
(b) 2 is the lowest and the only even prime number.
(c) 9 is the lowest odd composite number.
Co-prime Numbers
Two numbers are said to be co-prime if they do not have a common factor other than 1 or two numbers whose HCF is 1 called co-prime numbers.
Co-prime numbers needs not be prime numbers.
For example:
(i) 7 and 10 are co-prime.
(ii) 15 and 17 are co-prime.
Twin Prime Numbers
Twin prime numbers are the two prime numbers whose difference is 2.
For example:
(i) 3 and 5
(ii) 17 and 19
(iii) 41 and 43
(iv) 29 and 31
(v) 71 and 73.