Viết 2 giờ 15 phút dưới dạng hỗn số với đơn vị là giờ:

$1\dfrac{2}{3}$ 

\(3\dfrac{1}{3}\)  

\(3\dfrac{1}{4}\)           

\(1\dfrac{1}{3}\)

$ - \dfrac{{21}}{4}$   

\( - \dfrac{{11}}{4}\)  

\( - \dfrac{{10}}{4}\)

\( - \dfrac{5}{4}\)

$\dfrac{{19.20}}{{19 + 20}} = \dfrac{1}{{19}} + \dfrac{1}{{20}}$             

\(6\dfrac{{23}}{{11}} = \dfrac{{6.23 + 11}}{{11}}\)  

\(a\dfrac{a}{{99}} = \dfrac{{100a}}{{99}}\left( {a \in {N^*}} \right)\)

\(1\dfrac{{15}}{{23}} = \dfrac{{1.23}}{{15}}\)

$ - \dfrac{1}{4}$        

\(\dfrac{3}{2}\)  

\(\dfrac{1}{4}\)                 

\(\dfrac{3}{4}\)

$\dfrac{{11}}{6}$ 

\(\dfrac{7}{6}\)  

\(\dfrac{{13}}{6}\)     

\( - \dfrac{5}{6}\)

$x = 1$ 

\(x = 2\)  

\(x = 3\)

\(x = 4\)

$1\dfrac{1}{7}$ 

\(\dfrac{2}{7}\)  

\(\dfrac{6}{7}\)

\(\dfrac{7}{8}\)