-10/13 + 5/17 - 3/13 + 12/17 - 11/20                                              3/4 + -5/6 - 11/-12

(-10/13 - 3/13) + (5/17 + 12/17) - 11/20                                         3/4 - 5/6 - 11/-12

-13/13 + 17/17 - 11/20                                                                   9/12 - 10/12 - 1/-12

-1 + 1 - 11/20                                                                                 -1/12 - -1/12

=-11/20                                                                                           -1/12 + 1/12

                                                                                                        =0

                              k cho mk nhé   cảm ơn bạn rất nhiều

-5/2×(2/11+9/11)×(-5/7+15/7)

-5/2×1×10/7

-5/2×10/7

25/7

a, (-20) + 16 + (-34) + 20 = [(-20) + 20] + [16 + (-34)] = 0 + (-18) = (-18) b, 12 + 3.[39 - (5 - 2)²] = 12 + 3.[39 - 3²] = 12 + 3.[39 - 9] = 12 + 3.30 = 12 + 90 = 102

`2-3 3/4:(5/8-20%)`
`=2-3 3/4:(5/8-1/4)`
`=2-15/4:3/8`
`=2-10`
`=-8`

\(2-3\dfrac{3}{4}:\left(\dfrac{5}{8}-20\%\right)\)
\(=2-\dfrac{15}{4}:\left(\dfrac{5}{8}-\dfrac{20}{100}\right)\)

\(=\dfrac{2}{1}-\dfrac{15}{4}:\left(\dfrac{5}{8}-\dfrac{1}{5}\right)\)

\(=\dfrac{2}{1}-\dfrac{15}{4}:\left(\dfrac{25}{40}-\dfrac{8}{40}\right)\)

\(=\dfrac{2}{1}-\dfrac{15}{4}:\dfrac{17}{40}\)

\(=\dfrac{2}{1}-\dfrac{15}{4}.\dfrac{40}{17}\)

\(=\dfrac{2}{1}-\dfrac{600}{68}\)

\(=\dfrac{2}{1}-\dfrac{150}{17}\)

\(=\dfrac{34}{17}-\dfrac{150}{17}\)

\(=\dfrac{-116}{17}\)

\(2-3\dfrac{3}{4}:\left(\dfrac{5}{8}-20\%\right)\) 

\(=2-\dfrac{15}{4}:\left(\dfrac{5}{8}-\dfrac{1}{5}\right)\) 

\(=2-\dfrac{15}{4}:\dfrac{17}{40}\) 

\(=2-\dfrac{150}{17}\) 

\(=\dfrac{-116}{17}\)

a; - \(\dfrac{10}{13}\) + \(\dfrac{5}{17}\) - \(\dfrac{3}{13}\) + \(\dfrac{12}{17}\) - \(\dfrac{11}{20}\)

= - (\(\dfrac{10}{13}\) + \(\dfrac{3}{13}\)) + (\(\dfrac{5}{17}\) + \(\dfrac{12}{17}\)) - \(\dfrac{11}{20}\)

= - 1 + 1  - \(\dfrac{11}{20}\)

=   0 - \(\dfrac{11}{20}\)

= - \(\dfrac{11}{20}\)

b; \(\dfrac{3}{4}\) + \(\dfrac{-5}{6}\) - \(\dfrac{11}{-12}\)

= \(\dfrac{9}{12}\) - \(\dfrac{10}{12}\) + \(\dfrac{11}{12}\)

= \(\dfrac{10}{12}\)

= \(\dfrac{5}{6}\)

c; [13.\(\dfrac{4}{9}\) + 2.\(\dfrac{1}{9}\)] - 3.\(\dfrac{4}{9}\)

= [\(\dfrac{52}{9}\) + \(\dfrac{2}{9}\)] - \(\dfrac{4}{3}\)

= \(\dfrac{54}{9}\) - \(\dfrac{4}{3}\)

= \(\dfrac{14}{3}\)

d; 1,25 : \(\dfrac{15}{20}\) + [25% - \(\dfrac{5}{6}\)] : 4.\(\dfrac{2}{3}\)

= 1,25  x \(\dfrac{20}{15}\) + [\(\dfrac{1}{4}\) - \(\dfrac{5}{6}\)] : 4.\(\dfrac{2}{3}\)

=  \(\dfrac{5}{3}\) - \(\dfrac{7}{12}\) : 4 x \(\dfrac{2}{3}\)

= \(\dfrac{5}{3}\) - \(\dfrac{7}{48}\).\(\dfrac{2}{3}\)

= \(\dfrac{5}{3}\) - \(\dfrac{7}{72}\)

= \(\dfrac{113}{72}\)

=11+(-7).12+(-48):(-4)+25

=11+(-84)+12+25

=-73+12+25

= -61+25

=-36

11 + (- 7) . 12 + (- 48) : (- 4) + 5²

= 11 + (- 84) + 12 + 25

= - 73 + 37

= - 36