(a) ↔ (iii)
because –6 + (+1) = –5, which lies between –11 and –4.
(b ) ↔(i)
because +1 + (–11) = –10 which lies between –11 and –4.
(c) ↔ (iv)
because +7 + (–13) = –6 which lies between –11 and –4
(d) ↔(ii)
because –2 + (–5) = –7 which lies between –11 and –4.