(-1/5)²+1/5.2.(-1/2)³-1/2 (-1)³/15+(-2/3)²:2⅔-|-5/6| 32³.9⁵/8³.6⁶

$a,=\dfrac{1}{25}+\dfrac{1}{5}.2.\dfrac{-1}{8}-\dfrac{1}{2}=\dfrac{1}{25}-\dfrac{1}{20}-\dfrac{1}{2}=\dfrac{51}{100}$

$b,=\dfrac{-1}{15}+\dfrac{4}{9}.\dfrac{3}{8}-\dfrac{5}{6}=\dfrac{-1}{15}+\dfrac{1}{6}-\dfrac{5}{6}=\dfrac{-11}{15}$

$c,=\dfrac{2^{15}.3^{10}}{2^9.2^6.3^6}=3^4=81$