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 5 will do.
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.
Try 30
That's not a number, fifteen is a multiple of five if that's what you mean.
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.