Question

For which operations is the set {–1, 1} closed?

Choose all answers that are correct.

A.
addition

B.
subtraction

C.
multiplication

D.
division

Answer 1

hi :)

Answer 2

What do you think?

Answer 3

c?

Answer 4

C and ?

Answer 5

d?

Answer 6

Yep.

Answer 7

i dont understand closed? that just mean zero?

Answer 8

-1 + 1 = 0 - Not in the set
-1 - 1 = -2 - not in the set.
If the result of the action is in the set given, it is closed. If it isn't, it is not closed.
-1/1 = -1 - Is in the set, so therefore it is closed
-1*1 = -1 - is in the set, so therefore it is closed.

Answer 9

ok...

Answer 10

I know, it's tricky, I learned this last year, but it didn't make sense until this year. :P

Answer 11

yeah when i was in first grade my teacher held me back because they were lieing to the state

Answer 12

Ah okay.