Given example me sirf (1),(12),(13),(23) se hi kyu multiply kiya gya g (123) ya fir (231) etc etc se kyu ni

Example : Let G = S, and H = {(1), (13)). Then the left cosets of H in G are: (1) H = H, (12) H = {(12), (12)(13)) = {(12), (132)} = (132)H, (13) H = {(13), (1)} = H, (23) H {(23), (23)(13)} = {(23), (123)) = (123)H.