Đề bài

Thực hiện các phép tính sau:

a) $\frac{5}{{12}} + \frac{{21}}{8}.\frac{1}{{14}}$

b) $\frac{8}{{15}}.\frac{3}{{64}} - \frac{{13}}{{25}}.$

c) $\left( {\frac{{19}}{{21}} - \frac{2}{3}} \right).\frac{{28}}{{10}}$

d) $\left( {1 - \frac{5}{{17}}} \right).\left( {\frac{3}{8} - \frac{{{5^2}}}{{24}}} \right)$