Tính giá trị biểu thức: $A = \dfrac{{\dfrac{2}{3} - \dfrac{2}{5} + \dfrac{2}{{10}}}}{{\dfrac{8}{3} - \dfrac{8}{5} + \dfrac{8}{{10}}}} + \dfrac{1}{2}.$

$\dfrac{{22}}{{15}}$

$\dfrac{6}{8}$

$\dfrac{6}{{15}}$

$\dfrac{8}{{15}}$

$\dfrac{{a.d}}{{b.c}}$

$\dfrac{{a.c}}{{b.d}}$

$\dfrac{{a + c}}{{b + d}}$

$\dfrac{{a + d}}{{b + c}}$

Là số nguyên âm        

Là số nguyên dương

Là số hữu tỉ âm

Là số hữu tỉ dương

$\dfrac{3}{2}$

$ - \dfrac{3}{2}$

$\dfrac{2}{3}$

$ - \dfrac{2}{3}$

\(\dfrac{2}{3} + \dfrac{5}{4}\)

\(\dfrac{1}{6} + \dfrac{3}{2}\)

\(\dfrac{5}{3} + \dfrac{3}{2}\)          

\(1 + \dfrac{{13}}{{12}}\)

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

$\dfrac{3}{4}$

$\dfrac{2}{3}$

$\dfrac{3}{2}$

\(\dfrac{2}{3} - \dfrac{5}{7}\)

\(\dfrac{1}{{14}} - \dfrac{1}{7}\)

\(\dfrac{1}{2} - \dfrac{5}{7}\)

\(\dfrac{3}{{14}} - \dfrac{5}{{14}}\)