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

Toán Lớp 4: Tính nhanh: a, 8 x 427 x 3 + 6 x 573 x 4 b, 6 x 1235 x 20 – 5 x 235 x 24 c, (145 x 99 +145) – 143 x 101 – 143 d, 54 x 47 – 47 x 53 –

Toán Lớp 4: Tính nhanh:
a, 8 x 427 x 3 + 6 x 573 x 4
b, 6 x 1235 x 20 – 5 x 235 x 24
c, (145 x 99 +145) – 143 x 101 – 143
d, 54 x 47 – 47 x 53 – 20 – 27

Comments ( 2 )

  1. a. 8 xx 427 xx 3 + 6 xx 573 xx 4
    =(8 xx 3) xx 423 +(6 xx 4) xx 573
    =24 xx 423 + 24 xx 573
    =24 xx (423+573)
    =24000
    b. 6 xx 1235 xx 20 – 5 xx 235 xx 24
    =(6xx20)xx1235-(5xx24)xx235
    =120xx1235-120xx235
    =120xx(1235-235)
    =120000
    c. (145 xx 99 +145) – 143 xx 101 – 143 
    =(145 xx 99 +145) – (143 xx 101 – 143)
    =145xx(99+1)-143xx(101-1)
    =145xx100-143xx100
    =200
    d. 54 xx 47 – 47 xx 53 – 20 – 27
    =47xx(54-53)-20-27
    =47xx1-20-27
    =47-20-27
    =27-27
    =0
     

  2. Lời giải và giải thích chi tiết:
    a)
    8 × 427 × 3 + 6 × 573 × 4
    = 24 × 427 + 24 × 573
    = 24 × (427 + 573)
    = 24 × 1000
    = 24000
    b)
    6 × 1235 × 20 – 5 × 235 × 24
    = 120 × 1235 – 120 × 235
    = 120 × (1235 – 235)
    = 120 × 1000
    = 120000
    c)
    text(Sửa đề)
    (145 × 99 + 145) – 143 × 101 + 143
    = (145 × 99 + 145) – (143 × 101 – 143)
    = 145 × 100 – 143 × 100
    = 100 × (145 – 143)
    = 200
    d)
    54 × 47 – 47 × 53 – 20 – 27
    = 47 × (54 – 53) – 20 – 27
    = 47 – 20 – 27
    = 0

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