Hãy tính: ​\({4 \over 7}:\left( {{2 \over 3}.{8 \over 7}} \right)\)

* Hướng dẫn giải

Ta có:

\({4 \over 7}:\left( {{2 \over 3}.{8 \over 7}} \right) \)

\(= {4 \over 7}:\left( {{{2.8} \over {3.7}}} \right) \)

\(= {4 \over 7}:{{16} \over {21}} \)

\(= {4 \over 7}.{{21} \over {16}} \)

\(= {{4.21} \over {7.16}} \)

\(= {{1.3} \over {1.4}} = {3 \over 4}\)