Trong các khẳng định sau khẳng định nào đúng?

$\dfrac{{2 - 40}}{2} = \dfrac{{ - 38}}{2}$

$\dfrac{{16 - 5}}{2} = \dfrac{{11}}{2}$

$\dfrac{{16 - 40}}{{16}} =  - 40$

$\dfrac{{8.(2 - 5)}}{{16}} = \dfrac{{ - 3}}{2}$

Đoạn thẳng $OA$

Đoạn thẳng $OB$

Đoạn thẳng $AB$

Đường thẳng $AB$

$\dfrac{3}{2}$

$\dfrac{{ - 3}}{2}$

$\dfrac{{ - 2}}{3}$   

$\dfrac{1}{3}$

$3$

$2$

$0$

$1$

$10$

$0$

$\dfrac{{ - 1}}{{10}}$        

$\dfrac{1}{{10}}$

$\dfrac{1}{{27}} - \dfrac{1}{9} = \dfrac{0}{{18}}$ 

$\dfrac{1}{{27}} - \dfrac{3}{{27}} = \dfrac{{1 - 3}}{{27}} = \dfrac{{ - 2}}{{27}}$

$\dfrac{1}{{27}} - \dfrac{3}{{27}} = \dfrac{2}{{27}}$

$\dfrac{1}{{27}} - \dfrac{3}{{27}} = \dfrac{{ - 2}}{0}$