\(\frac{9}{20}-\frac{8}{15}\cdot\frac{5}{12}=\frac{9}{20}-\frac{8\cdot5}{15\cdot12}=\frac{9}{20}-\frac{2\cdot1}{3\cdot3}=\frac{9}{20}-\frac{2}{9}=\frac{81}{180}-\frac{40}{180}=\frac{41}{180}\)
\(\frac{9}{20}-\frac{8}{15}\times\frac{5}{12}=\frac{9}{20}-\frac{8\times5}{15\times12}=\frac{9}{20}-\frac{2\times4\times5}{3\times5\times3\times4}=\frac{9}{20}-\frac{2}{9}=\frac{81}{180}-\frac{40}{180}=\frac{41}{180}\)