Advertisements (Quảng cáo)
Tính:
\(\left( { – 3,2} \right).{{ – 15} \over {64}} + \left( {0,8 – 2{4 \over {15}}} \right):3{2 \over 3}.\)
Hướng dẫn làm bài:
\(\left( { – 3,2} \right).{{ – 15} \over {64}} + \left( {0,8 – 2{4 \over {15}}} \right):3{2 \over 3}.\)
\(= {{ – 32} \over {10}}.{{ – 15} \over {64}} + \left( {{8 \over {10}} – {{34} \over {15}}} \right):{{11} \over 3}\)
\( = {{ – 1} \over 2}.{{ – 3} \over 2} + \left( {{{24} \over {30}} – {{68} \over {30}}} \right):{{11} \over 3}\)
Advertisements (Quảng cáo)
\( = {3 \over 4} + {{ – 44} \over {30}}:{{11} \over 3} = {3 \over 4} + {{ – 44} \over {30}}.{3 \over {11}}\)
\(= {3 \over 4} + {{ – 4} \over {10}}.{1 \over 1} = {{ – 3} \over 4} + {{ – 4} \over {10}}\)
\( = {{15} \over {20}} + {{ – 8} \over {20}} = {7 \over {20}}\)