Ta có :

1996 + 3992 + 5988 + 7984

          = 1 x 1996 + 2 x 1996 + 3 x 1996 + 4 x 1996

          = (1 + 2 + 3 + 4) x 1996

          = 10 x 1996

          = 19960

(ko bt đúng sai đâu nhá!)

2)

200 : [ 117 -( 23-2.3 ) ]

= 200:[117-(23-6)]

= 200:[117-17]

= 200:100

= 2

4)

2020-[45-(6-1)² ] + 1992⁰

= 2020 - [45-5² ] + 1992⁰

= 2020 - 40² + 1

= 2020 - 1600 + 1

= 420 +1

= 421

6)

480 : [75 + (7² - 8.3) : 5 ] + 2021⁰ 

= 480 : [ 75+( 49 - 24 ): 5 ] + 2021⁰

= 480: [ 75 + 25 : 5 ] + 2021⁰

= 480 : [ 75 + 5 ] + 2021⁰

= 480 : 80 + 1 

= 6 + 1

= 7

8)

2⁴ . 5 - [ 131 - (13 - 4)² ]

= 10⁴ - [ 131 - 9² ]

= 10⁴ - 50

= 10000 - 50

= 9950

(1992⁰ = 1 : 2021⁰=1)

Đáp án A

cos 119 0 + i sin 119 0 = sin − 29 0 + i cos − 29 0 ;

1 2 cos 119 0 + i sin 119 0 8 cos 59 0 + i sin 59 0 = 2 cos − 29 0 + i sin − 29 0 cos 59 0 + i sin 59 0 = 2 cos 30 0 + i sin 30 0 = 3 + i .

2 x 3 x 4 x 8 x 50 x 25 x 125

          = 3 x 2 x 4 x 50 x 8 x 25 x 125

          = 3 x (2 x 50) x (4 x 25) x (8 x 125)

          = 30 000 000.

472 + 34 - ( 472 - 16 )

= 472 + 34 - 472 + 16

= ( 472 - 472 ) + ( 34 + 16 )

= 0 + 50

= 50

Học tốt nhé bạn !

472 +34 - ( 472 - 16 )

= (34 + 16 ) -( 472 - 472 ) 

= 50 - 0

= 50

472 + 34 - ( 472 - 16 )

= 472 + 34 - 472 - 16

= ( 472 - 472 ) + ( 34 - 16 )

= 0 + 18 = 18

Vậy 472 + 34 - ( 472 - 16 ) = 18

Chúc bạn hok tốt nhé !!! ^-^ 

\(\left(-3\right)^2.\left(-5\right)-\left[\left(-95\right)+\left(13+7\right)^2\right]\)

\(=9.\left(-5\right)-\left(-95+20^2\right)\)

\(=-45+95-400\)

\(=50-400\)

\(=-350\)

a, Ta có:
1996 + 3992 + 5988 + 7984
= 1 x 1996 + 2 x 1996 + 3 x 1996 + 4 x 1996
= (1 + 2 + 3 + 4) x 1996
= 10 x 1996
= 19960
b, 2 x 3 x 4 x 8 x 50 x 25 x 125
= 3 x 2 x 4 x 50 x 8 x 25 x 125
= 3 x (2 x 50) x (4 x 25) x (8 x 125)

= 30 000 000.

          \(\frac{5}{9}.\frac{-4}{17}+\frac{-13}{17}.\frac{5}{9}+2\frac{4}{9}\)

\(=\)\(\frac{5}{9}.\left(\frac{-4}{17}+\frac{-13}{17}\right)+2\frac{4}{9}\)

\(=\frac{5}{9}.\left(-1\right)+\frac{22}{9}\)

\(=\frac{5}{9}+\frac{22}{9}\)

\(=3\)