The set {-1, 0, 1} is not closed under which operation?
multiplication
division
subtraction
all of the above

I am so stuck and confused please help?!

Question

The set {-1, 0, 1} is not closed under which operation? 
       multiplication
       division
       subtraction
       all of the above

I am so stuck and confused please help?!

anonymous · Answer

I think the answer is subtraction but I am not sure if it is right

misty1212 · Answer

HI!!

misty1212 · Answer

certainly not subtraction since $(-1-1=-2$ is not in the set !

misty1212 · Answer

what about $1+1$?

misty1212 · Answer

wow!!

misty1212 · Answer

look at all the ghosts!

misty1212 · Answer

15 ghosts, more then the movie 12 ghosts!!

anonymous · Answer

hahah, I think in multiplication the set would be closed because
1 times 0 is 0
-1 times 0 is 0
and -1 times 1 is -1

misty1212 · Answer

yes

anonymous · Answer

do you know how you find out if a set is closed under division?

misty1212 · Answer

and certainly not division since $1\div0$ is not even a number

misty1212 · Answer

like the math teachers say, "you cannot divide by zero"
i tried it once though
still shaking ...

anonymous · Answer

hahahaha :)
the question confuses me because its not A and both B and C could be answers but it is not D either

misty1212 · Answer

pick "multiplication"

anonymous · Answer

multiplication? But the question says which one would not close the set?