=28/15*3/4-(104/195+1/4)*24/47-(1+4/13)

=7/5-2/5-1-4/13

=-4/13

\(1\dfrac{13}{15}.0,75-\left(\dfrac{8}{15}+25\%\right).\dfrac{24}{47}-3\dfrac{12}{13}:3\)

\(=\dfrac{28}{15}.\dfrac{3}{4}-\left(\dfrac{8}{15}+\dfrac{1}{4}\right).\dfrac{24}{47}-\dfrac{51}{13}:3\)

\(=\dfrac{7}{5}-\dfrac{47}{60}.\dfrac{24}{47}-\dfrac{17}{13}\)

\(=\dfrac{7}{5}-\dfrac{2}{5}-\dfrac{17}{13}\)

\(=1-\dfrac{17}{13}=-\dfrac{4}{13}\)

=27.(18+103-120)/33.(15+12)

= 27.1/33.27

=1/33

\(=\frac{27\left(18+103-120\right)}{33\left(15+12\right)}\)

\(=\frac{27\times1}{33\times27}\)

\(=\frac{1}{33}\)

mink không chép lại đề nha bạn

\(\dfrac{28}{15}\).\(\dfrac{3}{4}\)\(-\)\(\left(\dfrac{104}{195}+\dfrac{1}{4}\right).\dfrac{24}{47}-\dfrac{51}{13}:3\)

\(\dfrac{7}{5}\)\(-\dfrac{23}{60}\).\(\dfrac{24}{47}\)\(-\dfrac{17}{13}\)

\(\dfrac{7}{5}\)\(-\dfrac{46}{235}\)\(-\dfrac{17}{13}\)

\(\dfrac{283}{235}\)\(-\dfrac{17}{13}\)

= (đến đây bạn tự tính ra kết quả nhé)

\(1\dfrac{13}{15}\cdot0,75-\left(\dfrac{104}{195}+25\%\right)\cdot\dfrac{24}{47}-3\dfrac{12}{13}:3\)

\(=\dfrac{28}{15}\cdot\dfrac{3}{4}-\left(\dfrac{8}{15}+\dfrac{1}{4}\right)\cdot\dfrac{24}{47}-\dfrac{51}{13}\cdot\dfrac{1}{3}\\ =\dfrac{7}{5}-\dfrac{47}{60}\cdot\dfrac{24}{47}-\dfrac{17}{13}\\ =\dfrac{7}{5}-\dfrac{2}{5}-\dfrac{17}{13}\)

\(=1-\dfrac{17}{13}=-\dfrac{4}{13}\)

Công thức tổng quát:n thuộc N

3/((10n+3)(10n+13))

=(3/10)((1/(10n+3))-(1/(10n+13)))

1/13 + 3/(13×23) + 3/(23.33) + ....+3/(1993.2003)

=(3/10)(1/3-1/13+1/13-1/23+...+1/1993-1/2003)

=(3/10)(1/3-1/2003)

=200/2003

Nếu là tính thường thì:

=0-(8/15+1/4).24/47-51/13.1/3

=-(32/60+15/60).24/47-17/13

=-47/60.24/47-17/13

=-2/5-17/13

=-26/65-85/65

=-111/65

=-1/46/65

nếu là tính nhanh thì Mình ko biết sorry!

1\(\dfrac{13}{15}.0,75-\left(\dfrac{104}{195}+25\%\right).\dfrac{24}{47}-3\dfrac{12}{13}:3\)

=\(\dfrac{28}{15}.\dfrac{3}{4}-\dfrac{47}{60}.\dfrac{24}{47}-\dfrac{51}{13}.\dfrac{1}{3}\)

=\(\dfrac{7}{5}-\dfrac{2}{5}-\dfrac{17}{13}\)

=\(1-\dfrac{17}{13}\)

=\(-\dfrac{4}{13}\)

Toàn câu dễ nên bạn tự làm đi.

Trong lúc bạn đánh xong bài này thì bạn có thể làm xong rồi đó.

Đừng có ỷ lại vào người khác ,động não lên.

a: \(=\dfrac{5^8\cdot2^8}{5^{10}\cdot2^{10}}=\dfrac{1}{100}\)

b: =7/2+2/7

=49/14+4/14

=53/14

c: \(=\dfrac{11}{12}\cdot\dfrac{16}{33}\cdot\dfrac{3}{5}=\dfrac{1}{3}\cdot\dfrac{3}{5}\cdot\dfrac{4}{3}=\dfrac{1}{5}\cdot\dfrac{4}{3}=\dfrac{4}{15}\)

d: \(=15\cdot\dfrac{4}{9}\cdot\dfrac{-7}{3}=\dfrac{15}{27}\cdot\left(-28\right)=-28\cdot\dfrac{5}{9}=-\dfrac{140}{9}\)

g: \(=\left(\dfrac{21}{47}+\dfrac{26}{47}\right)+\left(\dfrac{9}{45}+\dfrac{36}{45}\right)=1+1=2\)

j: =12*4/9+4/3

=16/3+4/3

=20/3

\(\frac{-35}{47}-\left(\frac{25}{13}-\frac{35}{47}\right)+\frac{12}{13}\)

\(=\frac{-35}{47}-\frac{25}{13}+\frac{35}{47}+\frac{12}{13}\)

\(=\left(\frac{-35}{47}+\frac{35}{47}\right)+\left(\frac{-25}{13}+\frac{12}{13}\right)\)

\(=0-1\)

\(=-1\)

_Chúc bạn học tốt_

\(\frac{-35}{47}-\left(\frac{25}{13}-\frac{35}{47}\right)+\frac{12}{13}\)

=\(\frac{-35}{47}-\frac{720}{611}+\frac{12}{13}\)

=\(-1\)

        \(-\frac{35}{47}-\left(\frac{25}{13}-\frac{35}{47}\right)+\frac{12}{13}\)............ k cho mik nhé!  ...............

\(=\)\(-\frac{35}{47}-\frac{25}{13}+\frac{35}{47}+\frac{12}{13}\)

\(=-\frac{35}{47}+\frac{35}{47}-\frac{25}{13}+\frac{12}{13}\)

\(=-\frac{25}{13}+\frac{12}{13}\)\(=-\frac{13}{13}=-1\)

a, \(\begin{array}{l}A = \dfrac{{ - 3}}{{14}} + \dfrac{2}{{13}} + \dfrac{{ - 25}}{{14}} + \dfrac{{ - 15}}{{13}}\\A = \left( {\dfrac{{ - 3}}{{14}} + \dfrac{{ - 25}}{{14}}} \right) + \left( {\dfrac{2}{{13}} + \dfrac{{ - 15}}{{13}}} \right)\\A = \dfrac{{ - 3 + \left( { - 25} \right)}}{{14}} + \dfrac{{2 + \left( { - 15} \right)}}{{13}}\\A = \dfrac{{ - 28}}{{14}} + \dfrac{{ - 13}}{{13}}\\A =  - 2 + (-1)\\A =  - 3\end{array}\)

b, 

Cách 1:

\(\begin{array}{l}B = \dfrac{5}{3}.\dfrac{7}{{25}} + \dfrac{5}{3}.\dfrac{{21}}{{25}} - \dfrac{5}{3}.\dfrac{7}{{25}}\\B = \left( {\dfrac{5}{3}.\dfrac{7}{{25}} - \dfrac{5}{3}.\dfrac{7}{{25}}} \right) + \dfrac{5}{3}.\dfrac{{21}}{{25}}\\B = 0 + \dfrac{5}{3}.\dfrac{{21}}{{25}}\\B = \dfrac{{5.21}}{{3.25}}\\B = \dfrac{7}{5}\end{array}\)

Cách 2:

\(B = \dfrac{5}{3}.\dfrac{7}{{25}} + \dfrac{5}{3}.\dfrac{{21}}{{25}} - \dfrac{5}{3}.\dfrac{7}{{25}}\\B = \dfrac{5}{3}.({\dfrac{7}{{25}} -\dfrac{7}{{25}} + \dfrac{{21}}{{25}}})\\B =  \dfrac{5}{3}.\dfrac{{21}}{{25}}\\B = \dfrac{{5.21}}{{3.25}}\\B = \dfrac{7}{5}\)