PHẦN II. TỰ LUẬN

Thực hiện phép tính (tính hợp lí nếu có thể):

    a) \(\frac{6}{5} - \frac{1}{5}:\frac{3}{{10}}\);  

    b) \(914,75:5 + 211,2:5 - 101,95:5\);

    c) \(\frac{2}{7} + \frac{5}{7}.\left( {60\%  - 0,25} \right).{\left( { - 2} \right)^2}\).

a) \(\frac{6}{5} - \frac{1}{5}:\frac{3}{{10}}\)

\( = \frac{6}{5} - \frac{1}{5}.\frac{{10}}{3}\)\( = \frac{6}{5} - \frac{2}{3}\)

\( = \frac{{18}}{{15}} - \frac{{10}}{{15}} = \frac{8}{{15}}\).

b) \(914,75:5 + 211,2:5 - 101,95:5\)

\( = \left( {914,75 + 211,2 - 101,95} \right):5\)

\( = 1024:5\)

\( = 204,8\).

c) \(\frac{2}{7} + \frac{5}{7}.\left( {60\%  - 0,25} \right).{\left( { - 2} \right)^2}\)

\( = \frac{2}{7} + \frac{5}{7}.\left( {\frac{{60}}{{100}} - \frac{{25}}{{100}}} \right).4\)

\( = \frac{2}{7} + \frac{5}{7}.4.\frac{{35}}{{100}}\)

\( = \frac{2}{7} + \frac{{20}}{7}.\frac{7}{{20}}\)

\[ = \frac{2}{7} + 1\]\[ = \frac{9}{7}\].