Tính nhanh a, 16. 50 .(-25 ) . ( -250 ) b, 125 . ( -51 ) . ( -2 )$^{3}$ . $( -1)^{100}$ c, -54 . 38 + 12 . ( -54 ) – 50 . ( -54 ) d, 65 . ( 87 – 1

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1. Đáp án+Giải thích các bước giải:

   $\\a)16.50 . (-25).( – 250)$ $\\ = 4.4.50.(-25).(-250)$ $\\\text{={[4.(-25)].[4.(-250)]}.50}$ $\\\text{={(-100).(-1000)}.50}$ $\\=100000.50$ $\\=5000000$

   $\\b)125 . ( -51 ) . ( -2 )^3.(-1)^{100}$ $\\=125.(-51).(-8).1$ $\\=[125.(-8)].(-51)$ $\\=(-1000).(-51)$ $\\=51000$

   $\\c) -54 . 38 + 12 . ( -54 ) – 50 . ( -54 ) $ $\\=(-54).(38+12-50)$ $\\=(-54).(50-50)$ $\\=(-54).0$ $\\=0$

   $d) 65 . ( 87 – 17 ) – 87 . ( 17 -65 )$ $\\=65.87-65.17-87.17-87.65$ $\\=65.(87-87)+17.(-65-87)$ $\\=65.0+17.(-152)$ $\\=0+(-2584)=-2584$

   $\\e) 87. ( 13 – 18 ) – 13 .( 87 +18 )$ $\\=87.13-87.18-13.87+(-13).18$ $\\=87.(13-13)+18.[(-87)+(-13)]$ $\\=0+18.(-100)=-1800$

   $\\g, 74 . ( -41 ) – 41 . 26$ $\\=(-41).(74-26)$ $\\=(-41).48=-1968$

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2. Đáp án + giải thích bước giải :

   `a) 16 . 50 . (-25) . (-250)`

   `= [16 . (-25)] . [50 . (-250)]`

   `= -400 . (-12500)`

   `= 5000000`

   `b) 125 . (-51) . (-2)^3 . (-1)^{100}`

   `= -6375 . (-8) . 1`

   `= 51000 . 1`

   `= 51000`

   `c) -54 . 38 + 12 . (-54) – 50 . (-54)`

   `= -54 . (38 + 12 – 50)`

   `= -54 . 0`

   `= 0`

   `d) 65 . (87 – 17) – 87 . (17 – 65)`

   `= 65 . 70 – 87 . (-48)`

   `= 4550 – (-4176)`

   `= 8726`

   `e) 87 . | (13 – 18) – 13 (87 + 18)|`

   `= 87 . |-5 – 13 . 105|`

   `= 87 . |-5 – 1365|`

   `= 87 . |-1370|`

   `= 87 . 1370`

   `= 119190`

   `g) 74 . (-41) – 41 . 26`

   `= -74 . 41 – 41 . 26`

   `= 41 . (-74 – 26)`

   `= 41 . (-100)`

   `= -4100`

    

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