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

Toán Lớp 5: Đề: tính nhanh A) (145×99+145)-(143×101-143) B) (16×6+16×3+16)-(12×5+12×3+12×2) C)156×145+156×55 D) a+ax3+ax5+ax7=16

Toán Lớp 5: Đề: tính nhanh
A) (145×99+145)-(143×101-143)
B) (16×6+16×3+16)-(12×5+12×3+12×2)
C)156×145+156×55
D) a+ax3+ax5+ax7=16

Comments ( 2 )

  1. # tcv
    a )
    ( 145 x 99 + 145 ) – ( 143 x 101 + 143 ) = 145 x 100 – 143 x 100
    = 100 x ( 145 – 143 )
    = 100 x 2
    = 200
    b )
    ( 16 x 6 + 16 x 3 + 16 ) – ( 12 x 5 + 12 x 3 + 12 x 2 )
    = 16 x ( 6 + 3 + 1 ) – 12 x ( 5 + 3 + 2 )
    = 16 x 10 – 12 x 10
    = 10 x ( 16 – 12 )
    = 10 x 4
    = 40
    c )
    156 x 145 + 156 x 55
    = 156 x ( 145 + 55 )
    = 156 x 200
    = 31200
    d )
    a + a x 3 + a x 5 + a x 7 = 16
    a x 1 + a x 3 + a x 5 + a x 7 = 16
    a x ( 1 + 3 + 5 + 7 ) = 16
    a x 16 = 16
    a = 16 : 16
    a = 1

  2. a:(145×99+145)-(143×101-143)=200
    b: (16×6+16×3+16)-(12×5+12×3+12×2)=40
    c:156×145+156×55=31200
    d thì mình kông biết làm
    xin cho mình hay nhất

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