a. -37 + 54 + -70+ -163 + 246

= ( 54 + 246) + (-37 - 163 )  - 70

= 300 -200 -  70 = 30

b. -359+ 181+ -123+ 350+ -172

=(-178)+227+(-172)

=49+(-172)

=-123

c.-69+ 53+ 46+ -94+-14+ 78

=(-16)+(-48)+64

=-64+64

=0

d. 13- 12+ 11+10- 9+ 8- 7- 6+ 5- 4+ 3+2- 1

= 13 - (13 - 1) + (13 - 2) + (13 - 3) - (13 - 4) + (13 - 5) - (13 - 6) - (13 - 7) + (13 - 8) - (13 - 9) + (13 - 10) + (13 - 11) - (13 - 12)

= 13 - 13 + 1 + 13 - 2 + 13 - 3 - 13 + 4 + 13 - 5 - 13 + 6 - 13 + 7 + 13 - 8 - 13 + 9 + 13 - 10 + 13 - 11 - 13 + 12

= (13 - 13 + 13 + 13 - 13 + 13 - 13 - 13 + 13 - 13 + 13 + 13 - 13) + (1 - 2 - 3 + 4 - 5 + 6 + 7 - 8 + 9 - 10 - 11 = 12)

= 13 + 0

= 13

a) \(-37+54+\left(-70\right)+\left(-163\right)+246\)

\(=\left(246+54\right)-\left(37+163\right)-70\)

\(=300-200-70\)

\(=100-70=30\)

b) \(-359+181+\left(-123\right)+350+\left(-172\right)\)

\(=-359+181-123+350-172\)

\(=\left(-359+350\right)+\left(181-172\right)-123\)

\(=-9+9-123\)

\(=-123\)

c) \(-69+53+46+\left(-94\right)+\left(-14\right)+78\)

\(=-69+53+46-94-14+78\)

\(=\left(-69+78\right)+\left(53-14\right)+\left(46-94\right)\)

\(=9+39-48\)

\(=48-48=0\)

d) \(13-12+11+10-9+8-7-6+5-4+3+2-1\)

\(=\left(13-12\right)+\left(11+10\right)-\left(9-8\right)-\left(7+6\right)+\left(5-4\right)+\left(3+2-1\right)\)

\(=1+21-1-13+1+5\)

\(=21-13+1+5\)

\(=8+1+5=9+5=14\)

Bài 1:

\(a,=\left(156-56\right)^2=100^2=10000\\ b,=\left(x-y\right)^2-4z^2=\left(x-y-2z\right)\left(x-y+2z\right)\)

Bài 2:

\(a,=\left(x-y\right)\left(x+y\right)-5\left(x-y\right)=\left(x-y\right)\left(x+y-5\right)\\ b,=x^2+2x-6x-12=\left(x+2\right)\left(x-6\right)\\ c,=3\left(x^2-2xy-16+y^2\right)=3\left[\left(x-y\right)^2-16\right]\\ =3\left(x-y-4\right)\left(x-y+4\right)\)

25x5x4x27x2=27000.

k cho minh voi

\(25.5.4.27.2\)

\(=\left(25.4\right).\left(5.2\right).27\)

\(=100.10.27\)

\(=1000.27\)

\(=27000\)

25.5.4.27.2 = 27000

k nha 

25.5.4.27.2=(25.4).(5.2).27

               =100.10.27

               =1000.27 

               =27000

25 x 5 x 4 x 27 x 2

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

= 100 x  10 x 27

= 1000 x 27

= 27000

=270000 nhé bạn

1) (63:3) :3 

=21 : 3

=7

2) 25 .5 .4 .27 .2

=(25.4) . (5.2) .27

=100. 10 . 27

=1000.27

=27000

1, (63 : 3) : 3

= 21 : 3

= 7

2, 25.5.4.27.2

= (25.4).(4.2.27)

= 100.216

= 21600

Nhầm

2, 25.5.4.27.2

= (25.4).(5.2).27

= 100.10.27

= 1000.27

= 27000

25.5.4.27.2

= (25.4).(5.2).2 

=100.10.27

=27000

25 . 5 . 4 . 27 . 2

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

= 100 . 10 . 27

= 1000 . 27

= 27000

25.5.4.27.2

=(25.4).(5.2).27

=100.10.27

=1000.27

=27000

28.64+28.36

=28.(64+36)

=28.100

=2800

25 . 5 . 4 . 27 . 2                                                                                     28 . 64 + 28 . 36

= ( 25 . 4 ) . ( 27 . 2 ) . 5                                                                       = 28 . ( 64 + 36 )

= 100 . 54 . 5                                                                                         = 28 . 100

= 5400 . 5                                                                                               = 2800

= 27000 

25.5.4.27.2 

= ( 25 . 2 ) . ( 5 .4 ) .27 

= 100 . 20 . 27

= 2000 . 27

= 54000

28 . 64 + 28 . 36

= 28 . ( 64 + 36 )

= 28 . 100

= 2800

\(25.5.4.27.2=\left(25.4\right).\left(5.2\right).27=100.10.27=27.1000=27000\)

Ta có: 25.5.4.27.2 = 27 . (25.4) . (5.2)

      = 27 . 100 . 10 = 27000

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

                          = 100 . 10 . 27

                           = 1000 . 27

                          = 27000

\(25.5.4.27.2\)

\(\Rightarrow\left(25.4\right).\left(5.2\right).27\)

\(\Rightarrow100.10.27\)

\(\Rightarrow1000.27\)

\(\Rightarrow27.000\)

Đây là tính chất giao hoán ,kết hợp ấy

\(=27000\)

k nha