1. PLAYING WITH NUMBERS RULES FOR DIVISIBILITY

2. DIVISIBILITY BY 10 If a number has 0 in the ones place then it is divisible by 10. Illustration: 15, 20, 25, 30, 35, 105, 215, 6205, 3500 ………………….. All are divisible by 5 because they have 0 in ones place.

3. DIVISIBILITY BY 5 A number which has either 0 or 5 in its ones place then it is divisible by 5. Illustration: 10, 20, 30, 40, 100, 1000, 3200, 7015, 12500 ………………….. All are divisible by 5 because they either 0 or 5 in ones place.

4. DIVISIBILITY BY 2 A number is divisible by 2 if it has any of the digits 0, 2, 4, 6 or 8 in its ones place. Illustration: 10, 12, 14, 16, 2410, 4356, 1358, 2972, 5974………………….. All are divisible by 2 because they have any of 0, 2, 4, 6 or 8 in ones place.

5. DIVISIBILITY BY 3 In a number if sum of digits is a multiple of 3, then it is divisible by 3. Illustration: 21, 27, 36, 54, 219, 423,7455 ……………… All are Divisible by 3 because their sum of digits are multiple of 3

6. DIVISIBILITY BY 6 A number which is divisible by 2 and 3 both then it is divisible by 6. Illustration: 18, 24, 270, 642, 3024……………….. All are divisible by 6 because they are divisible by 2 and 3 both.

7. DIVISIBILITY BY 4 A number with 3 or more digits is divisible by 4 if the number formed by its last two digits (i.e. ones and tens) is divisible by4. Illustration: 212, 3516, 9532, 8840, 10424…………… All are divisible by 4 because their last two digits are divisible by 4.

8. DIVISIBILITY BY 8 A number with 4 or more digits is divisible by 8, if the number formed by the last three digits is divisible by 8. Illustration: 4888, 4216, 24168 ………………….. All are divisible by 8 because their last three digits are divisible by 8.

9. DIVISIBILITY BY 9 A number in which the sum of the digits of a number is divisible by 9, then the number is divisible by 9. Illustration: 9, 18, 27, 36, 45, 54, 4608, 5283……….. All are divisible by 9 because their sum of digits is divisible by 9.

10. DIVISIBILITY BY 11 If the difference between the sum of the digits at odd places (from the right) and the sum of the digits at even places (from the right) of the number is 0 or divisible by 11 then the number is divisible by 11. Illustration: 308, 1331, 61809 ………………….. All are divisible by 11 because of the rule above said.

11. EXERCISE