a)  − 105 + − 25 + ( − 105 ) + 50  

= 105 + 25 + ( - 105) + 50

= [105 + ( -105)] + ( 25 + 50 )

= 0 + 75 = 75

b)  465 + − 38 + − 465 − 12 − − 42

= 465 + ( - 38) + ( -465) – 12 – 42

= [ 465 + (- 465) ] – ( 12 + 42 )

= 0 – 54 = 0 + ( -54 ) = -54

c)  65. − 19 + − 19 .24 + − 19 .11

= ( - 19) . ( 65 + 24 + 11 )

= ( -19) . 100 = -1900

d)  − 3 2 + 2 3 − − 5 2 + 4 3

= 9 + 8 – 25 + 64 = 56

[(-105) + 40 ] + ( 10 + 50 )

= (-105) + ( 40 + 10 + 50 )

=(-105) + 100 = -5

 Áp dụng tính chất : kết hợp ( phép cộng )

[(-105)+40]+(10+50)

=(-105)+(40+10+50)

=(-105)+100

=-5

Áp dụng tính chất kết hợp(Phép cộng)

Học tốt nhé!

a) Ta có \(\dfrac{72}{95}\times\dfrac{105}{105}=\dfrac{72}{95}\times1=\dfrac{72}{95}=\dfrac{72}{95}\)

Vậy \(\dfrac{72}{95}=\dfrac{72}{95}\times\dfrac{105}{105}\)

b) Ta có \(\dfrac{72}{95}\times\dfrac{99}{98}=\dfrac{72}{95}\times\left(1+\dfrac{1}{98}\right)=\dfrac{72}{95}\times1+\dfrac{72}{95}\times\dfrac{1}{98}=\dfrac{72}{95}+\dfrac{72}{95}\times\dfrac{1}{98}>\dfrac{72}{95}\)Vậy \(\dfrac{72}{95}< \dfrac{72}{95}\times\dfrac{99}{98}\)

a) 72/95 ... 72/95 x 105/105
    72/95 ... 72/95 x 1   ( 105/105 = 1 )
    72/95   =   72/95 x 105/105
b) 72/95 ... 72/95 x 99/98
    72/95 x 1 ... 72/95 x 99/98   ( 99/98 > 1 )
    72/95  < 72/95 x 99/98

=8⁴-8⁴+105

=0+105=105

A, =47.(-1).12+12.(-53)

    =(-47).12+12.(-53)

     =[(-47)+(-53)].12

    =-100.12

    =-1200

Thực hiện phép tính (tính nhanh nếu có thể)

a, 47.(-12) + 12. (-53)

=(-47).12+12.(-53)

=12.[-47+(-53)]

=12.(-100)

=-1200

b, 106. (-3 - 105) - 106.(-105)

=106.[-3-105-(-105)]

=106.(-3)

=-318

\(a,47.\left(-12\right)+12.\left(-53\right)\)

\(=47.\left(-1\right).12+12.\left(-53\right)\)

\(=-47.12+12.\left(-53\right)\)

\(=12.\left[-47+\left(-53\right)\right]\)

\(=12.\left(-100\right)=-1200\)

\(b,106.\left(-3-105\right)-106.\left(-105\right)\)

\(=106.\left[-3-105-\left(-105\right)\right]\)

\(=106.\left(-3\right)=-318\)

a) (-2).(-6)^2+3.(-2)^3

=(-2).36-24=-96

b) (-6).4.(-7).25

=42.100=4200

c) (-85)-105+62

=-190+62=-128

d) 24.(-15)+(-15).75-15

=(-15).(24+75)-15

=(-15).99-15=-1500

câu a mình ghi nhầm 

a) (-2).(-6)^2+3.(-2)^3-62

b: \(\left(-99\right)+\left(-23\right)+\left(-201\right)+\left(-17\right)\)

\(=\left(-99-201\right)+\left(-23-17\right)\)

\(=-300-40=-340\)

c: \(\left(-105\right)-79-\left(-105\right)\)

\(=-105-79+105\)

\(=\left(105-105\right)-79\)

=0-79

=-79

d: \(\left(-230\right)-\left(-156\right)-\left(-230\right)\)

\(=-230+156+230\)

\(=\left(-230+230\right)+156\)

=0+156

=156

e: \(\left(-2021\right)+\left(-87\right)+2021+12\)

\(=\left(-2021+2021\right)+\left(-87+12\right)\)

=0+(-75)

=-75