A Points Very Much Important For Exams

A notes 

1. A factor of a number is an exact divisor of that number.

2. 1 is a factor of every number.

3. Every number is a factor of itself.

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

5. Number of factors of a given number are finite.

6. Every multiple of a number is greater than or equal to that number.

7. The number of multiples of a given number is infinite.

8. Every number is a multiple of itself.

9.The number 1 has only one factor (i.e. itself ).

10. 1 is neither a prime nor a composite number.

11. 2 is the smallest prime number which is even.

12. Every prime number except 2 is odd.

13. If a number has 0 in the ones place then it is divisible by 10.

14. A number which has either 0 or 5 in its ones place is divisible by 5. 

15. A number is divisible by 2 if it has any of the digits 0, 2, 4, 6 or 8 in its ones place.

16. If the sum of the digits is a multiple of 3, then the number is divisible by 3.

17.