a) $\frac{-1}{24}$ - ($\frac{1}{4}$ - ( $\frac{1}{2}$ - $\frac{7}{8}$ ) )

= $\frac{-1}{24}$ - ( $\frac{1}{4}$ - $\frac{1}{2}$ + $\frac{7}{8}$ )

= $\frac{-1}{24}$ - $\frac{1}{4}$ + $\frac{1}{2}$ - $\frac{7}{8}$ 

= $\frac{-1}{24}$ - $\frac{6}{24}$ + $\frac{12}{24}$ - $\frac{21}{24}$ 

= $\frac{-1 - 6 + 12 - 21}{24}$ 

= $\frac{-16}{24}$ 

= $\frac{-2}{3}$ 

b) ( $\frac{5}{7}$ - $\frac{7}{5}$ ) - ( $\frac{1}{2}$ - ( -$\frac{2}{7}$ - $\frac{1}{10}$ ) )

= $\frac{5}{7}$ -$\frac{7}{5}$ - ( $\frac{1}{2}$ + $\frac{2}{7}$ + $\frac{1}{10}$ )

= $\frac{5}{7}$ -$\frac{7}{5}$ - $\frac{1}{2}$ - $\frac{2}{7}$ - $\frac{1}{10}$ 

= $\frac{50}{70}$ -$\frac{98}{70}$ - $\frac{35}{70}$ - $\frac{20}{70}$ - $\frac{7}{70}$ 

= $\frac{50 - 98 - 35 - 20 - 7}{70}$ 

= $\frac{-110}{70}$ 

= $\frac{-11}{7}$ 

c) (-$\frac{1}{2}$) - (-$\frac{3}{5}$) + (-$\frac{1}{9}$) + $\frac{1}{71}$ - (-$\frac{2}{7}$) + $\frac{4}{35}$ - $\frac{7}{18}$  

= $\frac{-1}{2}$ + $\frac{3}{5}$ - $\frac{1}{9}$ + $\frac{1}{71}$ + $\frac{2}{7}$ + $\frac{4}{35}$ - $\frac{7}{18}$  

= ( $\frac{-1}{2}$ - $\frac{1}{9}$ - $\frac{7}{18}$  ) + ( $\frac{3}{5}$ + $\frac{2}{7}$ + $\frac{4}{35}$ ) + $\frac{1}{71}$

= ( $\frac{-9}{18}$ - $\frac{2}{18}$ - $\frac{7}{18}$  ) + ( $\frac{21}{35}$ + $\frac{10}{35}$ + $\frac{4}{35}$ ) + $\frac{1}{71}$

= $\frac{-18}{18}$ + $\frac{35}{35}$ + $\frac{1}{71}$ 

= - 1 + 1 + $\frac{1}{71}$ 

= $\frac{1}{71}$ 

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

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

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

=  - 8 + 1 + $\frac{6}{5}$

= $\frac{- 40}{5}$ + $\frac{5}{5}$ + $\frac{6}{5}$

= $\frac{- 29}{5}$ 

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