Question

If S = {integers} and subset B = {positive integers}, what is B'?

{…,−3, −2, −1}

{integers}

{ }

{1, 2, 3, 4, …}

Answer 1

B' means everything that is not B in S
B is 1,2,3,...
if you start with S (all negative and positive numbers) the not B is the negative numbers (but I would expect to see zero along with the neg numbers)