-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

a: =-5/11-6/11+1=-11/11+1=0

b: =-13/17-13/21-4/17=-1-13/21=-34/21

b: \(=-\dfrac{5}{12}\cdot\dfrac{9}{20}\cdot\dfrac{7}{17}=\dfrac{-21}{272}\)

d: \(=\dfrac{13}{17}\left(-\dfrac{4}{5}-\dfrac{3}{4}\right)=\dfrac{13}{17}\cdot\dfrac{-31}{20}=\dfrac{-403}{340}\)

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.\(\dfrac{4}{9}\)

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

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

= \(\dfrac{14}{3}\)

Mình lớp 4 mà bạn

Với lại là bằng :

6''675

7785.,77

664'87'9776''8

Bài 1:

a: \(x=\dfrac{2}{3}:\dfrac{3}{5}=\dfrac{2}{3}\cdot\dfrac{5}{3}=\dfrac{10}{9}\)

b: \(x=\dfrac{17}{8}:\dfrac{7}{17}=\dfrac{17}{8}\cdot\dfrac{17}{7}=\dfrac{289}{56}\)

c: \(x=-\dfrac{3}{4}:\dfrac{7}{12}=\dfrac{-3}{4}\cdot\dfrac{12}{7}=\dfrac{-63}{28}=-\dfrac{9}{4}\)

d: \(\Leftrightarrow x\cdot\dfrac{1}{6}=\dfrac{3}{8}-\dfrac{1}{4}=\dfrac{1}{4}\)

hay \(x=\dfrac{1}{4}:\dfrac{1}{6}=\dfrac{3}{2}\)

e: \(\Leftrightarrow\dfrac{1}{2}:x=-4-\dfrac{1}{3}=-\dfrac{17}{3}\)

hay \(x=-\dfrac{1}{2}:\dfrac{17}{3}=\dfrac{-3}{34}\)

dad

a)2.13.15=(2.15).13

=30.13

=390

Ghi đầy đủ nha

bn có thể ghi rõ ràng đc ko?

a. 250 - 15( 6 + 5 )

=  250 - 15.11

=  250 - 165

=  85

b. ( 75 + 27 ) + ( 451 - 75 - 27 )

=  75 + 27 + 451 - 75 - 27

=  ( 75 - 75 ) + ( 27 - 27 ) + 451

=  0 + 0 + 451

=  451

c. 35( 17 - 6 ) - 17( 35 - 6 )

=  35.11 - 17.29

=  385 - 493

=  -108

d. 38( 17 - 12 ) - 17( 38 - 12 )

=  38.5 - 17.26

=  190 - 442

=  - 252

250-15.(6+5)=250-15.6+15.5=250-80+75=170+75=245

(75+27)+(451-75-27)=75+27+451-75-27=(75-75)+(27-27)+451=0+0+451=451

35.(17-6)-17.(35-6)=35.17-35.6-17.35-17.6=35.6-17.6=6.(35-17) anh tự tính kết quả nhé

D=cách làm như trên