Tính nhẩm: a, 9.24.25 b, 12.125.54 c, 64.125.875 d, 425.7.4 – 170.60 e, 8.9.14 + 6.17.12 + 19.4.18

0 bình luận về “Tính nhẩm: a, 9.24.25 b, 12.125.54 c, 64.125.875 d, 425.7.4 – 170.60 e, 8.9.14 + 6.17.12 + 19.4.18”

1. `a)9.24.25`

   `=9.25.24`

   `=9.[25(20+4)]`

   `=9.(25.20+25.4)`

   `=9.(500+100)`

   `=9.600`

   `=5400`

   `b)12.125.54`

   `=12.[125.(50+4)]`

   `=12.(125.50+125.4)`

   `=12.(6250+500)`

   `=12.6750`

   `=81000`

   `c)64.125.875`

   `=8.8.125.875`

   `=8.125.8.875`

   `=1000.7000`

   `=7000000`

   `d)425.7.4-170.60`

   `=425.4.7-170.10.6`

   `=1700.7-1700.6`

   `=1700(7-6)`

   `=1700.1`

   `=1700`

   `8.9.14+6.17.12+19.4.18`

   `=2.4.9.14+2.3.17.3.4+19.4.2.9`

   `=2.4.9.14+2.4.9.17+2.4.9.19`

   `=2.4.9.(14+17+19)`

   `=72.50`

   `=3600.`

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2. a, 9.24.25

   = 9.6.4.25

   = 54.100

   = 5400

   b, 12.125.54

   = 3.4.125.2.27

   = 1000.3.27

   = 1000.81

   = 81000

   c, 64.125.875

   = 8000.875

   = 7000000

   d, 425.7.4-170.60

   = 11900-10200

   = 1700

   e, 8.9.14+6.17.12+19.4.18

   = 8.9.14+6.12.17+4.18.19

   = 72.14+72.17+72.19

   = 72.(14+17+19)

   = 72.50

   = 3600

    

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