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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 6: Bài 9:Tính a) (-11).(-28)+(-9) .13 b) (-69).(-31)-(-15).12 c) [16-(-5)].(-7) d) [(-4).(-9)—6].[(-12)-(-7)] Bài 10:Tính nhanh các tích s

Toán Lớp 6: Bài 9:Tính
a) (-11).(-28)+(-9) .13
b) (-69).(-31)-(-15).12
c) [16-(-5)].(-7)
d) [(-4).(-9)—6].[(-12)-(-7)]
Bài 10:Tính nhanh các tích sau:
a) (-4).2.6.25.(-7).5
b) (-32).125.(-9).(-25)
c) 47.69.-31.(-47)
d) (-56)+8.(11+7)

Comments ( 2 )

  1. Bài 9:Tính
    a) (-11).(-28)+(-9) .13 
    = 308 + (-117)
    = 191
    b) (-69).(-31)-(-15).12
    = 2139 – (-180)
    = 2139 + 180
    = 2319
    c) [16-(-5)].(-7)
    = ( 16 + 5 ) . (-7)
    = 21 . (-7) 
    = -147
    d) [(-4).(-9)—6].[(-12)-(-7)]
    = ( 36 – 6 ) . ( -12 + 7 )
    = 30 . (-5)
    = -150
    Bài 10:Tính nhanh các tích sau:
    a) (-4).2.6.25.(-7).5
    = [(-4).25] . [2.5.(-7)] . 6
    = -100 . -70 . 6
    = 7000 . 6
    = 42 000
    b) (-32).125.(-9).(-25)
    = [(-25).(-32)] . [125.(-9)]
    = 800 . (-1125)
    = -900 000
    c) 47.69.-31.(-47)
    = 47.69 . 31.47
    = 47 . ( 31 . 69 )
    = 47 . 2139
    = 100 533
    d) (-56)+8.(11+7)
    = (-56) + 8 . 18
    = (-56) + 144
    = 88

  2. $\text{Bài 9:}$
    a) ( – 11 ) . ( – 28 ) + ( – 9 ) . 13
    = 308 + ( – 117 )
    = 191
    b) ( – 69 ) . ( – 31 ) – ( – 15 ) . 12
    = 2139 + 15 . 12
    = 2139 + 180
    = 2319
    c) [ 16 – ( – 5 ) ] . ( – 7 )
    = [ 16 + 5 ] . ( – 7 )
    = 21 . ( – 7 )
    = – 147
    d) [ ( – 4 ) . ( – 9 ) – 6 ] . [ ( – 12 ) – ( – 7 ) ]
    = [ 36 – 6 ] . [ – 12 – ( – 7 ) ]
    = 30 . ( – 5 )
    = – 150
    $\text{Bài 10:}$
    a) ( – 4 ) . 2 . 6 . 25 . ( – 7 ) . 5
    = ( – 4 . 5 ) . 6 . 25 . 2 . ( – 7 )
    = – 20 . 150 . 2 . ( – 7 )
    = – 3000 . 2 . ( – 7 )
    = – 6000 . ( – 7 )
    = 42000
    b) ( – 32 ) . 125 . ( – 9 ) . ( – 25 )
    = [ – 32 . ( – 25 ) ] . 125 . ( – 9 )
    = 800 . 125 . ( – 9 )
    = 100000 . ( – 9 )
    = – 900000
    $\text{Sửa đề:}$
    c) 47 . 69 . ( – 31 ) . ( – 47 )
    = 47 . ( 69 + 31 )
    = 47 . 100
    = 4700
    d) ( – 56 ) + 8 . ( 11 + 7 )
    = – 56 + 8 . 11 + 8 . 7
    = – 56 + 88 + 56
    = ( – 56 + 56 ) + 88
    = 0 + 88
    = 88

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222-9+11+12:2*14+14 = ? ( )