a) \( 8\dfrac{2}{5}= \dfrac{8 \times 5 + 2}{5} =\dfrac{42}{5}\) ;
b) \( 5\dfrac{3}{4}=\dfrac{5 \times 4 +3}{4} =\dfrac{23}{4}\) ;
c) \( 4\dfrac{3}{7}= \dfrac{4 \times 7 + 3}{7} =\dfrac{31}{7}\) ;
d) \( 2\dfrac{1}{10}= \dfrac{2 \times 10 + 1}{10} =\dfrac{21}{10}\) .