Any number divided by itself is the same as ' 1 '.
31.880
31.880
One.
X divided by -Y is the same as -X divided by Y. Or - (X/Y)
It will be 3.
Technically, any number can be divided by any and all non-zero numbers, but I'll assume you mean evenly. There is no number that is evenly divisible by nine but not three because 9 is equal to 3x3. So when you divide by 9 it is the same as dividing by 3 twice.
24
30
1
The same number you started with.
Any number divided by 1 (one) would equal that same number.