Tính: ​\(B = \left( {3{1 \over 3}.1,9 + 19,5:4{1 \over 3}} \right).\left( {{{62} \over {75}} - {4 \over {25}}} \right)\)

* Hướng dẫn giải

\(\eqalign{
& B = \left( {3{1 \over 3}.1,9 + 19,5:4{1 \over 3}} \right).\left( {{{62} \over {75}} - {4 \over {25}}} \right) \cr 
& = \left( {{{10} \over 3}.{{19} \over {10}} + {{39} \over {2}}:{{13} \over 3}} \right).\left( {{{62} \over {75}} - {{12} \over {75}}} \right)  \cr 
& = \left( {{{19} \over 3} + {9 \over 2}} \right).{2 \over 3} = \left( {{{38} \over 6} + {{27} \over 6}} \right).{2 \over 3} \cr 
& = {{65} \over 6}.{2 \over 3} = {{65} \over 9} \cr} \)

Vậy \(B = \dfrac{{65}}{9}\)