\(\dfrac{3}{6}+\dfrac{12}{18}-\dfrac{1}{9}=\dfrac{9}{18}+\dfrac{12}{18}-\dfrac{2}{18}=\dfrac{21}{18}-\dfrac{2}{18}=\dfrac{19}{18}\)
\(\dfrac{1}{2}+\dfrac{6}{18}-\dfrac{1}{9}=\dfrac{9}{18}+\dfrac{12}{18}-\dfrac{2}{18}=\dfrac{9+12-2}{18}=\dfrac{19}{18}\)