**Even Numbers :**

Any Number that **can be divided exactly by 2**

The digit in once
place is **0**, **2**, **4**, **6** or **8**

**Ex: 2,6,12,18,20**

**Odd Numbers :**

Any integer that **cannot** be **divided exactly by 2**

** The digit
in once place is 1, 3, 5, 7 or 9**

**Ex :**** 7,9,15,19**

**Factor**

A number which divides the other number exactly is called a
**factor **of that number

· 1 is a factor of every number and is the smallest of all factors.

· Every number is a factor of itself and is the greatest of its factors.

· Every factor is less than or equal to the given number.

· Number of factors of a given number is countable

**Prime Numbers:**

These numbers whose only factors are 1 and the number itself

are called **prime numbers**.

Ex : 3,5,7,11,13,17

**Composite numbers:**

Numbers having more than two factors are called composite numbers.

Ex : 4,6,10,12

· The number 1 has only one factor (i.e. itself) so, 1 is neither prime nor composite.

**Co-Primes or Relatively Prime:**

The numbers which have only 1 as the common factor are called co-primes or relatively prime

Ex : (5,8) (10,11)

·We can say that "Only two primes are co-primes but all the co-primes need not be primes."

**Twin Primes:**

Twin primes are prime numbers that differ from each other by two

Ex : (3,5) (5,7) (11,13)

**Highest Common Factor (HCF):**

The Highest Common Factor (HCF) of two or more given numbers is the highest (or greatest) of their common factors. It is also called as Greatest Common Divisor (GCD)

**Least common Multiple (LCM):**

The least common multiple of two or more given numbers is the lowest (or smallest or least) of their common multiples

· Product of LCM and HCF of the two numbers = Product of the two numbers

Very good informations thank you so much keep going all bless you sir