Tính (13 9/11:38/49-5 2/11:38/49):(49/38. 5/11)

* Hướng dẫn giải

$\left(13\frac{9}{11}:\frac{38}{49}-5\frac{2}{11}:\frac{38}{49}\right):\left(\frac{49}{38}.\frac{5}{11}\right)=\left\{\left(13+\frac{9}{11}\right).\frac{49}{38}-\left(5+\frac{2}{11}\right).\frac{49}{38}\right\}:\left(\frac{49}{38}.\frac{5}{11}\right)$

$\begin{array}{l}=\frac{49}{38}.\left(13-5+\frac{9}{11}-\frac{2}{11}\right):\left(\frac{49}{38}.\frac{5}{11}\right)=\frac{49}{38}.\left(8+\frac{7}{11}\right):\left(\frac{49}{38}.\frac{5}{11}\right)\\ =\left(8+\frac{7}{11}\right):\frac{5}{11}=19\end{array}$