б) Вычислите: \(\dfrac{3}{5}\cdot\dfrac{5}{21}+\dfrac{15}{28}:\dfrac{5}{84}\) разделить на \(5:\dfrac{1}{2}+10\), затем прибавить \(\dfrac{2: \frac{1}{2}+3:\frac{1}{3}}{\frac{1}{2}:2+\frac{1}{3}:3}\), умножить на \(\dfrac{1}{36}\) и вычесть \(1\dfrac{16}{35}\).

\[\frac{\frac35\cdot\frac5{21}+\frac{15}{28}:\frac5{84}}{5:\frac12+10}+\frac{2:\frac12+3:\frac13}{\frac12:2+\frac13:3}\cdot\frac1{36}-1\frac{16}{35}\]

\[\frac35\cdot\frac5{21}=\frac17,\qquad \frac{15}{28}:\frac5{84}=9,\qquad 5:\frac12+10=20.\]

\[\frac{\frac17+9}{20}=\frac{16}{35}.\]

\[2:\frac12+3:\frac13=4+9=13,\qquad \frac12:2+\frac13:3=\frac14+\frac19=\frac{13}{36}.\]

\[\frac{13}{\frac{13}{36}}\cdot\frac1{36}=1.\]

\[\frac{16}{35}+1-1\frac{16}{35}=0.\]

Ответ: \(0\).