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27 tháng 3

\(\left(\dfrac{5}{7}-\dfrac{7}{7}\right)-\left[0,2-\left(-\dfrac{2}{7}-\dfrac{1}{10}\right)\right]\)

=\(-\dfrac{2}{7}-\left[\dfrac{1}{5}+\dfrac{2}{7}+\dfrac{1}{10}\right]\)  

=\(-\dfrac{2}{7}-\dfrac{1}{5}-\dfrac{2}{7}-\dfrac{1}{10}\) 

=\(\left(-\dfrac{2}{7}-\dfrac{2}{7}\right)-\left(\dfrac{1}{5}+\dfrac{1}{10}\right)\) 

=\(-\dfrac{4}{7}-\left(\dfrac{2}{10}+\dfrac{1}{10}\right)\) 

=\(-\dfrac{4}{7}-\dfrac{3}{10}\) 

=\(-\dfrac{40}{70}-\dfrac{21}{70}\)

=\(-\dfrac{61}{70}\)

 

 

27 tháng 3

   (3 - \(\dfrac{1}{4}\) + \(\dfrac{2}{3}\)) - (5 - \(\dfrac{1}{3}\) - \(\dfrac{5}{6}\)) - (6 - \(\dfrac{7}{4}\) - \(\dfrac{3}{2}\))

= 3 - \(\dfrac{1}{4}\) + \(\dfrac{2}{3}\) - 5 + \(\dfrac{1}{3}\) + \(\dfrac{5}{6}\) - 6 + \(\dfrac{7}{4}\) + \(\dfrac{3}{2}\)

= (3 - 5 - 6) + ( \(\dfrac{7}{4}\) - \(\dfrac{1}{4}\)) + (\(\dfrac{2}{3}\) + \(\dfrac{1}{3}\)) +  \(\dfrac{3}{2}\) + \(\dfrac{5}{6}\)

= - 8  + \(\dfrac{3}{2}\) + 1 + \(\dfrac{3}{2}\) + \(\dfrac{5}{6}\)

= (- 8 + 1) + (\(\dfrac{3}{2}\) + \(\dfrac{3}{2}\)) + \(\dfrac{5}{6}\)

= -7 + 3 + \(\dfrac{5}{6}\)

= - 4 + \(\dfrac{5}{6}\)

\(\dfrac{-19}{6}\)

1.  25 : 5,7 = 250/57

2.  30:2.8.4 = 480

3.  20:2^2.14= 70

4.  125:5^3.170= 170

5.  64:2^5.30.4=240

6.  (25:5^2.30): 15.7=14

       bạn à! Nhiều quá mình ko làm hết được. sorry nha.^-^                     

20 tháng 7 2018

dù dài quá nhưng cố  gắng giúp mình làm hết nha

23 tháng 5

  \(\dfrac{1}{2}+\dfrac{3}{4}-\left(\dfrac{3}{4}-\dfrac{4}{5}\right)\)

=\(\dfrac{1}{2}+\dfrac{3}{4}-\dfrac{3}{4}+\dfrac{4}{5}\)

=\(\left(\dfrac{1}{2}+\dfrac{4}{5}\right)+\left(\dfrac{3}{4}-\dfrac{3}{4}\right)\) 

=\(\left(\dfrac{5}{10}+\dfrac{8}{10}\right)+0\)

=\(\dfrac{13}{10}\)

23 tháng 5

\(-\dfrac{7}{25}.\dfrac{11}{13}+\left(-\dfrac{7}{25}\right).\dfrac{2}{13}-\dfrac{18}{25}\)

=\(-\dfrac{7}{25}.\cdot\left(\dfrac{11}{13}+\dfrac{2}{13}\right)-\dfrac{18}{25}\) 

=\(-\dfrac{7}{25}.1-\dfrac{18}{25}\) 

=\(-\dfrac{7}{25}-\dfrac{18}{25}\) 

=\(-\dfrac{25}{25}\) = \(-1\)

29 tháng 1 2023

\(a,\dfrac{1}{2}+\left(-\dfrac{3}{4}\right)=\dfrac{2}{4}+\left(-\dfrac{3}{4}\right)=-\dfrac{1}{4}\)

\(b,\dfrac{2}{5}+\left(-\dfrac{1}{16}\right)+\left(-\dfrac{9}{5}\right)+\left(-\dfrac{5}{16}\right)=\left(\dfrac{2}{5}-\dfrac{9}{5}\right)-\left(\dfrac{1}{16}+\dfrac{5}{16}\right)=\dfrac{-7}{5}-1=\dfrac{-12}{5}\)

\(c,\dfrac{-2}{13}+\dfrac{8}{15}+\dfrac{10}{20}+\dfrac{15}{13}+\left(-\dfrac{23}{15}\right)=\left(\dfrac{-2}{13}+\dfrac{15}{13}\right)+\left(\dfrac{8}{15}+\dfrac{-23}{15}\right)+\dfrac{1}{2}=1+\left(-1\right)+\dfrac{1}{2}=\dfrac{1}{2}\)

29 tháng 1 2023

(Cho mik làm lại nha)

\(a,\dfrac{1}{2}+\left(-\dfrac{3}{4}\right)=\dfrac{2}{4}+\left(-\dfrac{3}{4}\right)=-\dfrac{1}{4}\)

\(a,\dfrac{2}{5}+\left(-\dfrac{1}{16}\right)+\left(-\dfrac{9}{5}\right)+\left(-\dfrac{5}{16}\right)=\left(\dfrac{2}{5}+\dfrac{-9}{5}\right)-\left(\dfrac{1}{16}+\dfrac{5}{16}\right)=\dfrac{-7}{5}-\dfrac{6}{16}=\dfrac{-71}{40}\)

\(c,\dfrac{-2}{13}+\dfrac{8}{15}+\dfrac{10}{20}+\dfrac{15}{13}+\left(-\dfrac{23}{15}\right)=\left(\dfrac{-2}{13}+\dfrac{15}{13}\right)+\left(\dfrac{8}{15}+\dfrac{-23}{15}\right)+\dfrac{1}{2}=1+\left(-1\right)+\dfrac{1}{2}=\dfrac{1}{2}\)

7 tháng 4 2016

ko phải toán lớp 6

31 tháng 7 2016

5) 24*(15+49)+12*(50+42)

=24*64+12*92

=24*64+12*2*46

=24*64+24*46

=24*(64+46)

=24*110

=2640