Tính: \(\dfrac{5}{8}\; \cdot \dfrac{{ - 3}}{4}\)
\(\dfrac{{ - 1}}{{16}}\)
\( - 2\)
\(\dfrac{{ - 15}}{{32}}\)
\(\dfrac{{ - 5}}{{32}}\)
Tính: \(\dfrac{1}{{12}} \cdot \dfrac{8}{{ - 9}}\)
\(\dfrac{{ - 2}}{{27}}\)
\(\dfrac{{ - 4}}{9}\)
\(\dfrac{{ - 1}}{{18}}\)
\(\dfrac{{ - 3}}{2}\)
Kết quả của phép tính \(\left( { - 2} \right).\dfrac{3}{8}\) là
$\dfrac{{ - 16}}{8}$
\(\dfrac{{ - 13}}{8}\)
\(\dfrac{{ - 6}}{{16}}\)
\( - \dfrac{3}{4}\)
Chọn câu đúng.
\({\left( {\dfrac{{ - 7}}{6}} \right)^2} = \dfrac{{ - 49}}{{36}}\)
\({\left( {\dfrac{2}{3}} \right)^3} = \dfrac{8}{9}\)
\({\left( {\dfrac{2}{{ - 3}}} \right)^3} = \dfrac{8}{{ - 27}}\)
\({\left( {\dfrac{{ - 2}}{3}} \right)^4} = \dfrac{{ - 16}}{{81}}\)
Chọn câu sai.
\(\dfrac{2}{7}.\dfrac{{14}}{6} = \dfrac{2}{3}\)
\(25.\dfrac{{ - 4}}{{15}} = \dfrac{{ - 20}}{3}\)
\({\left( {\dfrac{2}{{ - 3}}} \right)^2}.\dfrac{9}{4} = 1\)
\(\dfrac{{ - 16}}{{25}}.\left( {\dfrac{{25}}{{ - 24}}} \right) = - \dfrac{2}{3}\)
Tính \(\dfrac{9}{{14}} \cdot \dfrac{{ - 5}}{8} \cdot \dfrac{{14}}{9}\)
\(\dfrac{{ - 15}}{{28}}\)
\(\dfrac{{ - 9}}{{28}}\)
\(\dfrac{{ - 5}}{8}\)
\(\dfrac{{ - 7}}{8}\)
Cho \(M = \dfrac{{17}}{5}.\dfrac{{ - 31}}{{125}}.\dfrac{1}{2}.\dfrac{{10}}{{17}}.{\left( {\dfrac{{ - 1}}{2}} \right)^3}\) và \(N = \left( {\dfrac{{17}}{{28}} + \dfrac{{28}}{{29}} - \dfrac{{19}}{{30}} - \dfrac{{20}}{{31}}} \right).\left( {\dfrac{{ - 5}}{{12}} + \dfrac{1}{4} + \dfrac{1}{6}} \right)\). Khi đó tổng \(M + N\) bằng
$\dfrac{{ - 62}}{{125}}$
\(\dfrac{{31}}{{1000}}\)
\(\dfrac{{ - 31}}{{100}}\)
\(\dfrac{{31}}{{100}}\)
Tính: \(B = \dfrac{{{2^2}}}{3} \cdot \dfrac{{{3^2}}}{8} \cdot \dfrac{{{4^2}}}{{15}} \cdot \dfrac{{{5^2}}}{{24}} \cdot \dfrac{{{6^2}}}{{35}} \cdot \dfrac{{{7^2}}}{{48}} \cdot \dfrac{{{8^2}}}{{63}} \cdot \dfrac{{{9^2}}}{{80}}\) ta được
$\dfrac{9}{5}$
\(\dfrac{3}{5}\)
\(3\)
\(\dfrac{6}{5}\)
Tính \(\dfrac{2}{3}:\dfrac{1}{2}\) bằng
$3$
\(1\)
\(\dfrac{1}{3}\)
\(\dfrac{4}{3}\)
Kết quả của phép tính \(\dfrac{{\left( { - 7} \right)}}{6}:\left( { - \dfrac{{14}}{3}} \right)\) là phân số có tử số là
$\dfrac{1}{4}$
\(\dfrac{1}{2}\)
\( - \dfrac{1}{2}\)
\(1\)
Tính \(\dfrac{2}{3}:\dfrac{7}{{12}}:\dfrac{4}{{18}}\)
$\dfrac{7}{{18}}$
\(\dfrac{9}{{14}}\)
\(\dfrac{{36}}{7}\)
\(\dfrac{{18}}{7}\)
Giá trị biểu thức \(M = \dfrac{5}{6}:{\left( {\dfrac{5}{2}} \right)^2} + \dfrac{7}{{15}}\) là phân số tối giản có dạng \(\dfrac{a}{b}\) với \(a > 0.\) Tính \(b + a.\)
$8$
\(\dfrac{9}{5}\)
\(\dfrac{3}{5}\)
\(2\)
Rút gọn \(N = \dfrac{{\dfrac{4}{{17}} - \dfrac{4}{{49}} - \dfrac{4}{{131}}}}{{\dfrac{3}{{17}} - \dfrac{3}{{49}} - \dfrac{3}{{131}}}}\) ta được
$\dfrac{4}{3}$
\(1\)
\(0\)
\( - \dfrac{4}{3}\)
Cho \(P = \left( {\dfrac{7}{{20}} + \dfrac{{11}}{{15}} - \dfrac{{15}}{{12}}} \right):\left( {\dfrac{{11}}{{20}} - \dfrac{{26}}{{45}}} \right)\) và \(Q = \dfrac{{5 - \dfrac{5}{3} + \dfrac{5}{9} - \dfrac{5}{{27}}}}{{8 - \dfrac{8}{3} + \dfrac{8}{9} - \dfrac{8}{{27}}}}:\dfrac{{15 - \dfrac{{15}}{{11}} + \dfrac{{15}}{{121}}}}{{16 - \dfrac{{16}}{{11}} + \dfrac{{16}}{{121}}}}\) . Chọn kết luận đúng:
$P > Q$
\(P < Q\)
\(P < - Q\)
\(P = Q\)
Tính giá trị biểu thức $A = \left( {\dfrac{{11}}{4}.\dfrac{{ - 5}}{9} - \dfrac{4}{9}.\dfrac{{11}}{4}} \right).\dfrac{8}{{33}}$
$A = - \dfrac{2}{3}$
$A = \dfrac{2}{3}$
$A = - \dfrac{3}{2}$
$A = \dfrac{3}{2}$
Cho \(A = \dfrac{{\left( {3\dfrac{2}{{15}} + \dfrac{1}{5}} \right):2\dfrac{1}{2}}}{{\left( {5\dfrac{3}{7} - 2\dfrac{1}{4}} \right):4\dfrac{{43}}{{56}}}}\) và \(B = \dfrac{{1,2:\left( {1\dfrac{1}{5}.1\dfrac{1}{4}} \right)}}{{0,32 + \dfrac{2}{{25}}}}\) . Chọn đáp án đúng.
\(A < - B\)
\(2A > B\)
\(A > B\)
\(A = B\)
Tính \(M = 1 + \dfrac{1}{2} + \dfrac{1}{{{2^2}}} + \dfrac{1}{{{2^3}}} + ... + \dfrac{1}{{{2^{99}}}} + \dfrac{2}{{{2^{100}}}}\)
\(\dfrac{1}{{{2^{99}}}}\)
\(\dfrac{{{2^{101}} - 2}}{{{2^{100}}}}\)
\(\dfrac{{{2^{101}} + 1}}{{{2^{100}}}}\)
\(\dfrac{{{2^{101}} - 1}}{{{2^{100}}}}\)
Tính giá trị biểu thức sau theo cách hợp lí
\(\left( {\dfrac{{20}}{7}.\dfrac{{ - 4}}{{ - 5}}} \right) + \left( {\dfrac{{20}}{7}.\dfrac{3}{{ - 5}}} \right)\)
\(\dfrac{4}{7}\)
\(\dfrac{{ - 4}}{7}\)
\( - 4\)
\(\dfrac{{11}}{7}\)
Tính giá trị của biểu thức.
\(\left( {\dfrac{{ - 2}}{{ - 5}}:\dfrac{3}{{ - 4}}} \right).\dfrac{4}{5}\)
\(\dfrac{{75}}{{32}}\)
\(\dfrac{{32}}{{75}}\)
\(\dfrac{{ - 32}}{{75}}\)
\(\dfrac{{ - 75}}{{32}}\)
Tính: \(\dfrac{{28}}{{15}}.\dfrac{1}{{{4^2}}}.3 + \left( {\dfrac{8}{{15}} - \dfrac{{69}}{{60}}.\dfrac{5}{{23}}} \right):\dfrac{{51}}{{54}}\)
\(\dfrac{1}{3}\)
\(\dfrac{{20}}{{13}}\)
\(3\)
\(\dfrac{{13}}{{20}}\)