= 10/15+21/15- 9/15
= 31/15 - 9/15
=22/15
\(\dfrac{2}{3}+\dfrac{7}{5}-\dfrac{3}{5}=\dfrac{2}{3}+\dfrac{7-3}{5}=\dfrac{2}{3}+\dfrac{4}{5}=\dfrac{10+12}{15}=\dfrac{22}{15}\)
\(\dfrac{13}{6}+\dfrac{5}{3}-2=\dfrac{13+10}{6}-2=\dfrac{23}{6}-2=\dfrac{23-12}{6}=\dfrac{11}{6}\)