\(A=\dfrac{1}{3}-\dfrac{3}{4}-\left(-\dfrac{3}{5}\right)+\dfrac{1}{15}-\dfrac{2}{9}-\dfrac{1}{36}\)
\(=\dfrac{1}{3}-\dfrac{3}{4}+\dfrac{3}{5}+\dfrac{1}{15}-\dfrac{2}{9}-\dfrac{1}{36}\)
\(=\left(\dfrac{1}{3}+\dfrac{3}{5}+\dfrac{1}{15}\right)-\left(\dfrac{3}{4}+\dfrac{2}{9}+\dfrac{1}{36}\right)\)
\(=\dfrac{5+9+1}{15}-\dfrac{27+8+1}{36}\)
=0