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

what do you think?

What is 1 + 1 ? So is it closed under addition?


What is 1 - 1 ? So is it closed under subtraction?

What is 1 x 1?
What is 1 x (-1)?
What is (-1) x 1?
What is (-1) x (-1)? so is it closed under multiplication?

What is 1 \(\div\) 1?
What is 1 \(\div\) (-1)?
What is (-1) \(\div\) 1?
What is (-1) \(\div\) (-1)? so is it closed under division?

Answer 2

you there?