Which set of integers is included in (-1,3]?
(1) {0,1,2,3} (3) {-1,0,1,2,3,4}
(2) {-1,0,1,2} (4) {-2,-1,0,1,2,3}

We have to choose which set of integers is included in ( -1, 3 ]. Integers that are included in this set are: 0, 1, 2, 3. Set number 2 is not included because -1 is not among those integers. Set number 3 is not included because it has numbers - 1 and 4. Set number 4 is not included because numbers - 2 and - 1 are not in the interval ( - 1 . 3]. (1) { 0, 1, 2, 3 }.