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

Toán Lớp 6: Tính nhanh B=2021/2+2021/6+2021/12+…+2021/90

Home/ Toán Lớp 6: Tính nhanh B=2021/2+2021/6+2021/12+…+2021/90

Toán Lớp 6: Tính nhanh B=2021/2+2021/6+2021/12+…+2021/90

Tháng Tám 18, 2022 Toán học 2 Comments 0 views

Toán Lớp 6: Tính nhanh B=2021/2+2021/6+2021/12+…+2021/90

Comments ( 2 )

  1. maitrucloan
    maitrucloan
    18 Tháng Tám, 2022 at 3:25 sáng
    Reply
    B = 2021/2 + 2012/6 + 2021/12 + … + 2021/90
    => B = 2021/{1 .2} + 2021/{2.3} + 2021/{3.4} + … + 2021/{9.10}
    => B = 2021/1 – 2021/2 + 2021/2 – 2021/3 + 2021/3 – 2021/4 + … + 2021/9 – 2021/10
    => B = 2021/1 – 2021/10
    => B = 18189/10
    Vậy B = 18189/10
    #dtkc

  2. quynhthanhnghi
    quynhthanhnghi
    18 Tháng Tám, 2022 at 3:24 sáng
    Reply
    ~~ Bạn tham khảo nhé ~~
    B = \frac{2021}{2} + \frac{2021}{6} + \frac{2021}{12} + … + \frac{2021}{90}
    ⇒ B = \frac{2021}{1 . 2} + \frac{2021}{2 . 3} + \frac{2021}{3 . 4} + … + \frac{2021}{9 . 10}
    ⇒ B = \frac{2021}{1} – \frac{2021}{2} + \frac{2021}{2} – \frac{2021}{3} + \frac{2021}{3} – \frac{2021}{4} + … + \frac{2021}{9} – \frac{2021}{10}
    ⇒ B = \frac{2021}{1} – \frac{2021}{10}
    ⇒ B = \frac{2021 . 10 – 2021}{10}
    ⇒ B = \frac{2021 . 9}{10}
    ⇒ B = \frac{18189}{10}

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

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