(i) \(\frac{-8}{3}+(\frac{-1}{4})+(\frac{-11}{6})+\frac{3}{8}-3\)

= \(\frac{-8}{3}-\frac{1}{4}-\frac{11}{6}+\frac{3}{8}-3\)

= \(\frac{-8\times 8}{3\times 8}-\frac{1\times 6}{4\times 6}-\frac{11\times 4}{6\times 4}+\frac{3\times 3}{8\times 3}-\frac{3\times 24}{1\times 24}\)

= \(\frac{-64-6-44+9-72}{24}\)

 = \(\frac{-59\times 3}{8\times 3}\)

 = \(\frac{-59}{8}\)

(ii) \(\frac{6}{7}+1+(\frac{-7}{9})+(\frac{19}{21})+\frac{-12}{7}\)

= \(\frac{6\times 9}{7\times 9}+\frac{63}{63}-\frac{7\times 7}{9\times 7}-\frac{19\times 3}{21\times 3}-\frac{12\times 9}{7\times 9}\) 

= \(\frac{54}{63}+\frac{63}{63}-\frac{49}{63}+\frac{57}{63}-\frac{108}{63}\)

= \(\frac{54+63-49+57-108}{63}\)

= \(\frac{17}{63}\)

(iii) \(\frac{15}{2}+(\frac{9}{8})+(\frac{-11}{3})+6+\frac{-7}{6}\)

 = \(\frac{15}{2}+\frac{9}{8}-\frac{11}{3}+6-\frac{7}{6}\)

 = \(\frac{15\times 12}{2\times 12}+\frac{9\times 3}{8\times 3}-\frac{11\times 8}{3\times 8}+\frac{6\times 24}{1\times 24}-\frac{7\times 4}{6\times 4}\)

 = \(\frac{180+27-88+144-28}{24}\)

  = \(\frac{235}{24}\)

(iv) \(\frac{-7}{4}+0+(\frac{-9}{5})+(\frac{19}{10})+\frac{11}{14}\)

 = \(\frac{-7}{4}+0-\frac{9}{5}+\frac{19}{10}+\frac{11}{14}\)

= \(\frac{-7\times 35}{4\times 35}-\frac{9\times 28}{5\times 28}+\frac{19\times 14}{10\times 14}+\frac{11\times 10}{14\times 10}\)

= \(\frac{-245-252+266+110}{140}\)

= \(\frac{-121}{140}\)

(v) \(\frac{-7}{4}+(\frac{5}{3})+(\frac{-1}{2})+\frac{-5}{6}+2\)

 = \(\frac{-7}{4}+\frac{5}{3}-\frac{1}{2}-\frac{5}{6}+2\)

 = \(\frac{-7\times 6}{4\times 6}+\frac{5\times 8}{3\times 8}-\frac{1\times 12}{2\times 12}-\frac{5\times 4}{6\times 4}+\frac{2\times 24}{1\times 24}\)

 = \(\frac{-42+40-12-20+48}{24}\)

  = \(\frac{14}{24}\)

   = \(\frac{7}{12}\)