a ) 475

b) 269

c ) 27000

d ) 2800

a) \(86+375+14\)

\(=\left(86+14\right)+375\)

\(=100+375\)

\(=475\)

b) \(72+69+128\)

\(=\left(72+128\right)+69\)

\(=200+69\)

\(=269\)

c) \(25\cdot5\cdot4\cdot27\cdot2\)

\(=\left(25\cdot4\right)\cdot\left(5\cdot27\right)\cdot2\)

\(=100\cdot135\cdot20\)

\(=200\cdot135\)

\(=27000\)

d) \(28\cdot64+28\cdot36\)

\(=28\cdot\left(64+36\right)\)

\(=28\cdot100\)

\(=2800\)

a, 86+375+14

=(86+14)+375

=100+375

=475

b, 72+69+128

=(72+128)+69

=200+69

=269

c, 25.5.4.27.2

=(25.4)(5.2).27

=100.10.27

=1000.27

=27000

d, 28.64+28.36

=28(64+36)

=28.100

=2800

28/14=2

36/28=9/7

88/77=8/7

45/50=9/10

120/150=4/5

\(\dfrac{28}{14}=2\)
\(\dfrac{36}{28}=\dfrac{36:4}{28:4}=\dfrac{9}{7}\)
\(\dfrac{88}{77}=\dfrac{88:11}{77:11}=\dfrac{8}{7}\)
\(\dfrac{45}{50}=\dfrac{45:5}{50:5}=\dfrac{9}{10}\)
\(\dfrac{120}{150}=\dfrac{120:30}{150:30}=\dfrac{4}{5}\)

a: 86-x>86-4

=>-x>-4

hay x<4

b: x+28<28+3

=>x+28<31

hay x<3

x=0,1,2,3

x=0,1,2

a,86-x>86-4

86-x > 82

-x > 82 -86

-x> -4

x< 4

b,x+28<28+3

x+ 28 < 31

=> x < 31 - 28 

x < 3

\(86+357+14=457\)

\(72+69+128=275\)

\(25\cdot5\cdot4\cdot27\cdot2=27000\)

\(28\cdot64+28\cdot36=28\left(64+36\right)=2800\)

a) \(86+357+14=\left(86+14\right)+357=100+357=457\)

b) \(72+69+128=\left(72+128\right)+69=200+69=269\)

c) \(25.5.4.27.2=\left(25.4\right).\left(5.2\right).27=100.10.27=27000\)

d) \(28.64+28.36=28\left(64+36\right)=28.100=2800\)

a 86+14+357=100+357=457

b 72+128+69=200+69=269

c (25.4).(5.2).4.27

=100.10.4.27

=1000.4.27

=4000.27=64000

d 28. (64+36)=28.100=2800

nha

a) 86 + 357 + 14                                               b ) 72 + 69 +128

= ( 86 + 14 ) + 357                                              = ( 72 + 128 ) + 69

= 100 + 357                                                        = 200 + 69 = 269              

= 457

c) 25 . 5 . 4 . 27 .2

= ( 25.4).(5.2).27

= 100 x 10 x 27

= 1000 x 27

= 27 000

d) 28.64+28.36

= 28 . ( 64 + 36 )

= 28.100

= 2800

a) 86 + 357 + 14

= ( 86 + 14 )+ 357

= 100 + 357 

= 457

b) 72 + 69 + 128

= ( 72 + 128 ) + 69

= 200 + 69

= 269

c) 25 . 5 . 4 . 27 . 2 

= ( 25 . 4 ) . ( 5 . 2 ) . 27

= 100 . 10 . 27

= 1000 . 27

= 27000

a) 86 - x < 86 - 4

     86 - x < 82

             x < 86 - 82

             x < 4

b) hình như đề bài sai hay sao á

không phải sai đau

tra loi tiep cho minh di

a) 86 + 357 + 14 = (86 + 14) + 357 = 457;

b) 72 + 69 + 128 = (72 + 128) + 69 = 269;

c) 25 . 5 . 4 . 27 . 2 = (25 . 4) . ( 5 . 2) . 27 = 100.10.27 =  27 000;

d) 28 . 64 + 28 . 36 = 28.(64 + 36) = 2800

a) 457                 b) 269

c) 27000             d) 2800

-Học tốt-

a, (86+14) + 357 =100+357=457

b,(72+128)+69=200+69=269

c,25.4.5.2.27=100.10.27=27000

d,28.(64+36)=28.100=2800

câu cuối phải sửa thành d nhé

a=457

b=269

d=57

còn câu C ko có phép tính nên mình ko làm

a) 86+357+14=(86+14)+357=100+357=457

b) 72+69+128=(72+128)+69=200+69=269

c) 25.5.4.27.2=(25.4).(5.2).27=100.10.27=27000

d) 28.64+28.36=28.(64+36)=28.100=2800

Tomoyo Daidouji à phép nhân á bạn . 25 nhân 5 nhân 4 nhân 27 nhân 2