Question

Which sets of numbers are closed under addition?



Choose all answers that are correct.



A.


{0, 2, 5, 8}


B.


even integers


C.


rational numbers


D.


{0}

Answer 1

@Directrix

Answer 2

b and c?

Answer 3

@confluxepic

Answer 4

Why did you not choose Option D? Just wondering.

Answer 5

Because its just 0

Answer 6

It can be used to add to itself.
That is, it can be used more than once.

0 + 0 = 0 so {0} is closed w.r.t. addition.

Answer 7

Options B and C are correct as is Option D
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Option A is not.

{0, 2, 5, 8}

2 + 5 = 7 which is NOT in the set.

Answer 8

sorry internet messed up

Answer 9

It most likely is the OS website causing the problems.