Nội dung bài giảng
Tính
$$1{{13} \over {15}}.0,75 - \left( {{{104} \over {195}} + 25\% } \right).{{24} \over {47}} - 3{{12} \over {13}}:3$$
Giải
\(1{{13} \over {15}}.0,75 - \left( {{{104} \over {195}} + 25\% } \right).{{24} \over {47}} - 3{{12} \over {13}}:3\)
\(\eqalign{
& = {{28} \over {15}}.{3 \over 4} - \left( {{8 \over {15}} + {1 \over 4}} \right).{{24} \over {47}} - {{51} \over {13}}.{1 \over 3} \cr
& = {{28} \over {15}}.{3 \over 4} - \left( {{{32} \over {60}} + {{16} \over {60}}} \right).{{24} \over {47}} - {{51} \over {13}}.{1 \over 3} \cr
& = {7 \over 5} - {{47} \over {60}}.{{24} \over {47}} - {{17} \over {13}} \cr
& = {7 \over 5} - {2 \over 5} - 1 - {4 \over {13}} \cr
& = 1 - 1 - {4 \over {13}} \cr
& = - {4 \over {13}} \cr} \)