a: =20x71=1420

Hướng dẫn giải:

a) 280 x 71 : 14 = (280 : 14) x 71 = 20 x 71 = 1420

b) 125 x 88 : 11 = 125 x (88 : 11) = 125 x 8 = 1000

a) 35 x 2 x 9 x 5

= (35 x 9) x (2 x 5)

= (35 x 10 - 35) x 10

= (350 - 35) x 10

= 315 x 10 = 3150

b) 24 x 71 + 71 x 75 + 71

= 71 x (24+75+1)

=71 x 100

= 7100

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hoa hết mắt

ghi nhân thành . hoặc "x" đi

\(a,204\times\left(72+9+19\right)=204\times100=20400\)

\(b,968\times\left(125-210-4\right)=968\times-89=-86152\)

a,204.(72+9+19)

=204.100

=20400

b,968.(125-210-4-1)

=968.(-100)

=-96800

125 x 88 :11 =125 x (88 :11)

                     = 125 x 8 = 1000

 125 x 88 : 11 

= 125 x ( 88 : 11 )

= 125 x 8 

= 1000. 

125 x 88 : 11 = 125 x ( 88 : 11 )

                     = 125 x 8

                     = 1000

280 x  71 : 14=  1420 

do binh duc

\(280.71:14\)

\(=19880:14\)

\(=1420\)

   280 x 71 : 14

= ( 280 : 14 ) x 17

=  20        x 17

=  340  

nhiều thế

sfdhg 

a, 2 x 9 x 5 x 7 x 4 x 25

= 2³ x 3² x 5³ x 7 

= 63000

b, 6 x 14 x 5 x 25 x 3 x 4

= 2⁴ x 3² x 5³ x 7

= 126000

a) 2x9x5x7x4x25
= (2x5)x(4x25)x(9x7)
= 10x100x63
= 63000
b) 2x14x5x25x3x4
= (2x5)x(4x25)x(14x3)
= 10x100x42
= 42000