Whole numbersA whole number is a number which does not have a decimal point :4 is a whole number 3,7 is not a whole number - 100 is a whole number 0,01 is not a whole number. Divisibility of a number by another numberWe say that a number is divisible by another number if the result of their division is a whole number.12 is divisible by 2 because . 11 is not divisible by 3 because . 5 is not divisible by 2 because . 3123 is divisible by 9 because 125 is divisible by 5 because . 93 is not divisible by 5 because . Divisibility rulesA number is divisible by 2 if it ends with 0, 2, 4, 6, ou 8.A number is divisible by 3 if the sum of its figures is divisible by 3. A number is divisible by 5 if it ends with 0 or 5. A number is divisible by 9 if the sum of its figures is divisible by 9. Examples : The number 309 is divisible by 3 because the sum of its figures is 12 and 12 is divisible by 3 ( ). The number 1997 is not divisible by 9 because the sum of its figures is 26 and 26 is not divisible by 9 ( ). The number 44 is not divisible by 5 because it does not end with either 0 or 5. The number 123456 is divisible by 2 because it ends with 6. |