Tính giá trị của biểu thức sau: ...

A

- Hướng dẫn giải

Phương pháp giải:

 Áp dụng quy tắc tính giá trị biểu thức.

Giải chi tiết:

\(\begin{array}{l}a)\;\;4\frac{4}{{27}} - \left( {2\frac{2}{3} + 3\frac{1}{{27}}} \right)\\ = 4 + \frac{4}{{27}} - 2 - \frac{2}{3} - 3 - \frac{1}{{27}}\\ =  - 1 + \frac{4}{{27}} - \frac{1}{{27}} - \frac{2}{3}\\ =  - 1 + \frac{3}{{27}} - \frac{2}{3}\\ =  - 1 + \frac{1}{9} - \frac{2}{3}\\ = \frac{{ - 9}}{9} + \frac{1}{9} - \frac{6}{9} = \frac{{ - 14}}{9}.\end{array}\)

\(\begin{array}{l}b)\;\;2\frac{2}{5}:3\frac{3}{4} - 0,2\\ = \frac{{12}}{5}.\frac{4}{{15}} - \frac{1}{5}\\ = \frac{{16}}{{25}} - \frac{1}{5}\\ = \frac{{16}}{{25}} - \frac{5}{{25}}\\ = \frac{{11}}{{25}}.\end{array}\)

\(\begin{array}{l}
c)\;\;\frac{1}{2} - 12\% :1\frac{1}{5}\\
= \frac{1}{2} - \frac{{12}}{{100}}:\frac{6}{5}\\
= \frac{1}{2} - \frac{3}{{25}}.\frac{5}{6}\\
= \frac{1}{2} - \frac{1}{{10}}\\
= \frac{5}{{10}} - \frac{1}{{10}}\\
= \frac{4}{{10}} = \frac{2}{5}.
\end{array}\)

\(\begin{array}{l}
d)\;\;125\% .2\frac{1}{3} + 2\frac{2}{5}:3,5\\
= \frac{{125}}{{100}}.\frac{7}{3} + \frac{{12}}{5}:\frac{{35}}{{10}}\\
= \frac{{35}}{{12}} + \frac{{12}}{5}.\frac{2}{7}\\
= \frac{{35}}{{12}} + \frac{{24}}{{35}}\\
= \frac{{1225}}{{420}} + \frac{{288}}{{420}}\\
= \frac{{1513}}{{420}}.
\end{array}\)

Chọn A