When it is a factor of that particular number.
If the sum of the digits is a multiple of three, the whole number is a multiple of three.
Yes because the five has gas
You know that it is a multiple of 9 if it divides into 9 equally.
Any multiple of 105.
5,10,15,20,25,30
15
yes because if it has a zero or five at the end you know its a multiple of 5
When a number is a multiple of 5, the possible values of the ones digit are zero and five.
When it is a factor of that particular number.
That's not a number, fifteen is a multiple of five if that's what you mean.
Try 30
The probability will depend on how much you know and the extent of guessing.
If the sum of the digits is a multiple of three, the whole number is a multiple of three.
Yes. Any number that ends with 0 or 5 is a multiple of 5. (5x16=80)
Yes because the five has gas
I think you might mean "multiple." If the sum of a number's digits is a multiple of 9, the original number is as well. If you want to know how you know if a number is a factor of 9, memorize the numbers 1, 3 and 9.