\(\dfrac{6}{13}+\dfrac{14}{39}=\dfrac{18}{39}+\dfrac{14}{39}=\dfrac{32}{39}\)
\(\dfrac{4}{5}-\dfrac{4}{18}=\dfrac{72}{90}-\dfrac{20}{90}=\dfrac{52}{90}=\dfrac{26}{45}\)
\(\dfrac{3}{5}+\dfrac{7}{10}-\dfrac{13}{20}=\dfrac{12}{20}+\dfrac{14}{20}-\dfrac{13}{20}=\dfrac{26}{20}-\dfrac{13}{20}=\dfrac{13}{20}\)
\(\dfrac{2}{9}+\dfrac{3}{4}-\dfrac{5}{12}=\dfrac{8}{36}+\dfrac{27}{36}-\dfrac{15}{36}=\dfrac{35}{36}-\dfrac{15}{36}=\dfrac{20}{36}=\dfrac{5}{9}\)