Thực hiện phép tính một cách hợp lí:
\(\frac{0,8:\left(\frac{4}{5}.1,25\right)}{0,64-\frac{1}{25}}+\frac{\left(1,08-\frac{2}{25}\right):\frac{4}{7}}{\left(6\frac{5}{9}-3\frac{1}{4}\right).2\frac{2}{17}}\)
Thực hiện phép tính một cách hợp lí:
\(\frac{0,8:\left(\frac{4}{5}.1,25\right)}{0,64-\frac{1}{25}}+\frac{\left(1,08-\frac{2}{25}\right):\frac{4}{7}}{\left(6\frac{5}{9}-3\frac{1}{4}\right).2\frac{2}{17}}\)
Tính một cách hợp lí:
\(152+\left(-73\right)-\left(-18\right)-127\)
giúp em câu này với ạ.
152+ (−73)− (−18)− 127.
= 152 − 73 + 18 − 127.
= (152 + 18) - (73 + 127).
= 170 - 200 = -30.
= [152 - (-18)] - [127 - (-73)]
= (152 + 18) – (127 + 73)
= 170 - 200
= - 30
Tính một cách hợp lí:
\(A = \left( { - \dfrac{3}{{11}}} \right) + \dfrac{{11}}{8} - \dfrac{3}{8} + \left( { - \dfrac{8}{{11}}} \right)\)
\(\begin{array}{l}A = \left( { - \dfrac{3}{{11}}} \right) + \dfrac{{11}}{8} - \dfrac{3}{8} + \left( { - \dfrac{8}{{11}}} \right)\\ = \left[ {\left( { - \dfrac{3}{{11}}} \right) + \left( { - \dfrac{8}{{11}}} \right)} \right] + \left( {\dfrac{{11}}{8} - \dfrac{3}{8}} \right)\\ = \dfrac{{ - 11}}{{11}} + \dfrac{8}{8} = - 1 + 1 = 0\end{array}\)
Tính một cách hợp lí (nếu có thể):
\(1037+\left\{743-\left[1031-\left(+57\right)\right]\right\}\)
\(1037+\left\{743-\left[1031-\left(+57\right)\right]\right\}\)
\(=1037-1037+\left\{743-\left(+57\right)\right\}\)
\(=0+686\)
\(=686\)
\(1037+\left\{743-\left[1031-\left(+57\right)\right]\right\}\)
\(=1037+743-1031+57\)
\(=\left(743+57\right)+\left(1037-1031\right)\)
\(=800+6\)
\(=806\)
\(-29\times165+29\times65\)
\(\left\{215-\left[5\times(5\times16-25\times2)-\right]60\right\}\div5^3\)
tính hợp lí
\(-29\times165+29\times65=29\times\left(65-165\right)=29\times\left(-100\right)=-2900\\ ---\\ \left\{215-\left[5\times\left(5\times16-25\times2\right)\right]-60\right\}:5^3\\ =\left\{215-\left[5\times\left(80-50\right)\right]-60\right\}:125\\ =\left\{215-\left[5\times30\right]-60\right\}:125\\ =\left\{215-150-60\right\}:125=5:125=\dfrac{1}{25}\)
Tính hợp lí
\(\frac{\left(1,2\right)^{10}.25^5}{\left(-12\right)^8}\)
Tính giá trị của biểu thức sau một cách hợp lí:
\(B = \left( {\frac{{ - 3}}{{13}}} \right) + \frac{{16}}{{23}} + \left( {\frac{{ - 10}}{{13}}} \right) + \frac{5}{{11}} + \frac{7}{{23}}\)
\(\begin{array}{l}B = \left( {\frac{{ - 3}}{{13}}} \right) + \frac{{16}}{{23}} + \left( {\frac{{ - 10}}{{13}}} \right) + \frac{5}{{11}} + \frac{7}{{23}}\\ = \left[ {\left( {\frac{{ - 3}}{{13}}} \right) + \left( {\frac{{ - 10}}{{13}}} \right)} \right] + \left[ {\frac{{16}}{{23}} + \frac{7}{{23}}} \right] + \frac{5}{{11}}\\ = - 1 + 1 + \frac{5}{{11}}\\ = \frac{5}{{11}}\end{array}\)
`B= ( (-3)/13 + (-10)/13) + (16/23 + 7/23 ) +5/11`
`B= -13/13 + 23/23 +5/11`
`B=-1+1+5/11`
`B=0+5/11`
`B=5/11`
\(B=\left(-\dfrac{3}{13}\right)+\dfrac{16}{23}+\left(-\dfrac{10}{13}\right)+\dfrac{5}{11}+\dfrac{7}{23}\)
\(B=\left[\left(-\dfrac{3}{13}\right)+\left(-\dfrac{10}{13}\right)\right]+\left(\dfrac{16}{23}+\dfrac{7}{23}\right)+\dfrac{5}{11}\)
\(B=\left(-1\right)+1+\dfrac{5}{11}\)
\(B=\dfrac{5}{11}\)
Tính biểu thức sau :
\(\left(7-\dfrac{1}{2}-\dfrac{3}{4}\right):\left(5-\dfrac{1}{4}-\dfrac{5}{8}\right)\)
Tính một cách hợp lí :
\(065.78+2\dfrac{1}{5}.2020+0,35.78-2,2.2020\)
a: \(=\dfrac{28-2-3}{4}:\dfrac{40-2-5}{8}=\dfrac{23}{4}\cdot\dfrac{8}{33}=\dfrac{46}{33}\)
b: =78(0,65+0,35)+2020(2,2-2,2)
=78*1=78
\(\text{Thực hiện phép tính một cách hợp lý nhất (nếu có thể):}\)
\(1\)) \(\left(\dfrac{-8}{13}:\dfrac{3}{7}+\dfrac{-5}{13}:\dfrac{3}{7}\right).\dfrac{\left(-4\right)^3.\left|-3\right|}{7}\)
\(2\)) \(75\)\(\text{%}\)\(-\left(\dfrac{5}{2}+\dfrac{5}{3}\right)+\left(-\dfrac{1}{2}\right)^2\)
Giải:
1) (-8/13:3/7+-5/13:3/7).(-4)3.|-3|/7
=[7/3.(-8/13+-5/13)].-192/7
=[7/3.(-1)].-192/7
=-7/3.-192/7
=64
2) 75%-(5/2+5/3)+(-1/2)2
=3/4-25/6+1/4
=(3/4+1/4)-25/6
=1-25/6
=-19/6
Chúc bạn học tốt!
1) \(\left(\dfrac{-8}{13}:\dfrac{3}{7}+\dfrac{-5}{13}:\dfrac{3}{7}\right).\dfrac{\left(-4\right).|-3|}{7}\)
= \(\left[\left(\dfrac{-8}{13}+\dfrac{-5}{13}\right):\dfrac{3}{7}\right].\dfrac{-64.3}{7}\)
= \(\left[-1:\dfrac{3}{7}\right].\dfrac{-192}{7}\)
= \(\dfrac{-7}{3}.\dfrac{-192}{7}\)
= \(64\)
2) \(75\%-\left(\dfrac{5}{2}+\dfrac{5}{3}\right)+\left(-\dfrac{1}{2}\right)^2\)
= \(\dfrac{3}{4}-\dfrac{25}{6}+\dfrac{1}{4}\)
= \(\left(\dfrac{3}{4}+\dfrac{1}{4}\right)-\dfrac{25}{6}\)
= \(1-\dfrac{25}{6}\)
= \(\dfrac{-19}{6}\)
Chúc bạn học tốt !
thực hiện cách hợp lí
a) \(\left(-\frac{40}{5}.0,32.\frac{17}{20}\right):\frac{64}{75}\)
b) \(-1\frac{5}{7}.15+\frac{2}{7}.\left(-15\right)+\left(-105\right).\left(\frac{2}{3}-\frac{4}{5}+\frac{1}{7}\right)\)