a) 

A=(\(\dfrac{36}{12}\) - \(\dfrac{9}{12}\)+\(\dfrac{8}{12}\)) - ( \(\dfrac{24}{12}\) + \(\dfrac{16}{12}\) - \(\dfrac{18}{12}\) ) - ( \(\dfrac{12}{12}\) - \(\dfrac{21}{12}\) - \(\dfrac{54}{12}\))

= \(\dfrac{19}{12}\) - \(\dfrac{22}{12}\) - \(\dfrac{-63}{12}\)

= 5