Tính nhanh $\left( { - 2 - \dfrac{1}{3} - \dfrac{1}{5}} \right) - \left( {\dfrac{2}{3} - \dfrac{6}{5}} \right),$ta được kết quả là:

$\frac{5}{{21}}$

$\frac{2}{7}$

$\frac{{23}}{{21}}$

$\frac{{-23}}{{21}}$

0

$\frac{4}{9}$

$\begin{array}{l}\frac{{ - 4}}{3}\\\end{array}$

$\frac{{ - 68}}{{75}}$

$\dfrac{2}{{ - \,5}}$

$\dfrac{3}{4}$

$\dfrac{2}{3}$

$\dfrac{3}{2}$

$\dfrac{2}{3} + \dfrac{5}{4}$

$\dfrac{1}{6} + \dfrac{3}{2}$

$\dfrac{5}{3} + \dfrac{3}{2}$          

$1 + \dfrac{{13}}{{12}}$

$\frac{{194}}{{45}}$

$3\frac{3}{5}$

$\frac{{ - 14}}{5}$

$\frac{{ - 85}}{{59}}$

$\frac{{16}}{{25}}$

$\frac{{ - 19}}{{25}}$

$\frac{{19}}{{25}}$

$\frac{{ - 16}}{{25}}$

$- \dfrac{{12}}{5}$   

$\dfrac{3}{4}$

$\dfrac{2}{{15}}$

$\dfrac{{12}}{5}$