a)
[tex] \frac{21}{2} - ( \frac{3}{4} - (1 - \frac{5}{8}) = \frac{21}{2} - ( \frac{3}{4} - \frac{8 - 5}{8} )) = \frac{21}{2} - ( \frac{3}{4} - \frac{3}{8} )) = \frac{21}{2} - \frac{3}{8} = \frac{81}{8} [/tex]
b)
[tex] \frac{31}{4} + ( \frac{11}{4} + ( \frac{11}{6} - (1 - \frac{1}{12} ))) = \frac{31}{4} + ( \frac{11}{4} + ( \frac{11}{6} - \frac{11}{12} = \frac{31}{4} + ( \frac{11}{4} + \frac{11}{12} ) = \frac{31}{4} + \frac{11}{3} = \frac{137}{12} [/tex]
c)
[tex]( \frac{11}{3} - \frac{11}{5} ) + (2 - (1 - \frac{1}{15} )) = \frac{22}{15} + (2 - \frac{14}{15} ) = \frac{22}{15} + \frac{16}{15} = \frac{38}{15} [/tex]
d)
[tex](1 + (1 - \frac{2}{3} )) - (2 - \frac{1}{6} - \frac{11}{3} ) = (1 + \frac{1}{3} ) - ( - \frac{11}{6} ) = \frac{4}{3} + \frac{11}{6} = \frac{19}{6} [/tex]