\(\frac{31}{53}.\frac{17}{28}+\frac{31}{28}.\frac{11}{53}\)

=\(\frac{31}{28}.\frac{17}{53}+\frac{31}{28}.\frac{11}{53}\)

=\(\frac{31}{28}.\left(\frac{17}{53}+\frac{11}{53}\right)\)

=\(\frac{31}{28}.\frac{28}{53}\)

=\(\frac{31}{53}\)

\(\frac{31}{53}.\frac{17}{28}+\frac{31}{28}.\frac{11}{53}\)

\(=\frac{31}{53}.\frac{17}{28}+\frac{11}{28}.\frac{31}{53}\)

\(=\frac{31}{53}.\left(\frac{17}{28}+\frac{11}{28}\right)\)

\(=\frac{31}{53}.1\)

\(=\frac{31}{53}\)

\(\frac{31}{53}\times\frac{17}{28}+\frac{31}{28}\times\frac{11}{53}\)

\(=\frac{31}{53}\times\frac{17}{28}+\frac{31}{53}\times\frac{11}{28}\)

\(=\frac{31}{53}\times\left(\frac{17}{28}+\frac{11}{28}\right)\)

\(=\frac{31}{53}\times1\)

\(=\frac{31}{53}\)

(34 - 53 + 28) - (34 - 53 - 21)

= 34 - 53 + 38 - 34 + 53 + 21

= (34 - 34) - (53 - 53) + (38 + 21)

= 0 - 0 + 59 

= 59

thank bạn

45-58+(-45)+(+58)-3=45-58-45+58-3=(45-45)+(58-58)-3=-3

(-57)-(-12)+3-(-57)=-57+12+3+57=(-57+57)+12+3=15

-(-24)-(-30)+(-24)-30+8=24+30-24-30+8=(24-24)+(30-30)+8=8

-(-12)+(+19)-(+12)+8-19=12+19-12+8-19=(12-12)+(19-19)+8=8

47-(-53)+(-47)-(+53)=47+53-47-53=(47-47)+(53-53)=0

-(+28)+32-(-28)+(-34)=-28+32+28-34=(-28+28)-(34-32)=-2

15-(+72)+(-15)+(+72)=15-72-15+72=(15-15)+(72-72)=0

20-(+46)+(-25)-(-46)=20-46-25+46=(20-25)+(46-46)=-5

28-(-32)+(-28)-32+5=28+32-28-32+5=(28-28)+(32-32)+5=5

-75+(-49)+(+75)+49-12=-75-49+75+49-12=(-75+75)+(49-49)-12=-12

\(...=45-58-45+58-3=-3\)

\(...=-57+12+3+57=15\)

\(...=24+30-24-30+8=8\)

\(...=12+19-12+8-19=8\)

\(...=47+53-47-53=0\)

\(...=-28+32+28-34=-2\)

\(...=15-72-15+72=0\)

\(...=20-46-25+46=-5\)

\(=...28+32-28-32+5=5\)

\(...=-75-49+75+49-12=-12\)

bằng 22

  (28+46)+(53-28-31-46)

=53-31+28-28+46-46

=53-31

=22

a. 37. 38 + 62. 37

= 37 . (38 + 62)

= 37 . 100

= 3700

b. 28. 64 + 28. 36

= 28 . (64 + 36)

= 28 . 100

= 2800

=273

mk k pạn rùi, k mk đi pạn

SỐ ĐÓ LÀ

273

AI K MÌNH MÌNH 

K LẠI CHO

NHA CÁC BN

\(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{36}\\{36}\end{array}}\\\hline{\,\,\,\,72}\end{array}\)                                       \(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{73}\\{17}\end{array}}\\\hline{\,\,\,90}\end{array}\)

\(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{28}\\{53}\end{array}}\\\hline{\,\,\,81}\end{array}\)                                       \(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{25}\\{35}\end{array}}\\\hline{\,\,\,60}\end{array}\)