Advertisements (Quảng cáo)
Tính:
a) \( – {8 \over 5} + \left( { – 3{1 \over 4}} \right) – {2 \over 3}\)
b) \(6{1 \over 5} – \left( {{{ – 3} \over 4}} \right) + \left( {4{2 \over {10}}} \right)\)
c) \( – 4 + \left( { – 5{1 \over 8}} \right) + \left( {{{ – 3} \over 4}} \right)\)
d) \(3{1 \over 2} + \left( { – {2 \over 3}} \right) – {{0,42} \over {0,84}}\)
Advertisements (Quảng cáo)
\(\eqalign{ & a) – {8 \over 5} + \left( { – 3{1 \over 4}} \right) – {2 \over 3} = {{ – 8} \over 5} – {{13} \over 4} – {2 \over 3} = {{ – 96} \over {60}} – {{195} \over {60}} – {{40} \over {60}} = {{ – 331} \over {60}} \cr & b)6{1 \over 5} – \left( {{{ – 3} \over 4}} \right) + \left( {4{2 \over {10}}} \right) = {{31} \over 5} + {3 \over 4} + {{42} \over {10}} = {{124} \over {20}} + {5 \over {20}} + {{84} \over {20}} = {{223} \over {20}} \cr & c) – 4 + \left( { – 5{1 \over 8}} \right) + \left( { – {3 \over 4}} \right) = – 4 – {{41} \over 8} – {3 \over 4} = – {{32} \over 8} – {{41} \over 8} – {6 \over 8} = {{ – 79} \over 8} \cr & d)3{1 \over 2} + \left( { – {2 \over 3}} \right) – {{0,42} \over {0,84}} = {7 \over 2} – {2 \over 3} – {{42} \over {84}} = {7 \over 2} – {2 \over 3} – {1 \over 2} = {{21} \over 6} – {4 \over 6} – {3 \over 6} = {{14} \over 6} = {7 \over 3} \cr} \)