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

Toán Lớp 6: ????????????????????????????????????????????????????????????????Tính: 5/2+5/4+5/12+…+5/9900

Toán Lớp 6: ????????????????????????????????????????????????????????????????Tính:
5/2+5/4+5/12+…+5/9900

Comments ( 2 )

  1. Giải đáp:
    $\text{ $\dfrac{99}{20}$}$
    Lời giải và giải thích chi tiết:
    $\text{Đặt A = $\dfrac{5}{2}$ + $\dfrac{5}{6}$ + $\dfrac{5}{12}$ +…+ $\dfrac{5}{9900}$}$
    $\text{= 5($\dfrac{1}{2}$ + $\dfrac{1}{6}$ + $\dfrac{1}{12}$ +…+ $\dfrac{1}{9900}$)}$
    $\text{= 5($\dfrac{1}{1.2}$ + $\dfrac{1}{2.3}$ + $\dfrac{1}{3.4}$ +…+ $\dfrac{1}{99.100}$)}$
    $\text{= 5(1 – $\dfrac{1}{2}$ + $\dfrac{1}{2}$ – $\dfrac{1}{3}$ + $\dfrac{1}{3}$ – $\dfrac{1}{4}$ +…+ $\dfrac{1}{99}$ – $\dfrac{1}{100}$}$
    $\text{= 5 – $\dfrac{1}{20}$}$
    $\text{= $\dfrac{100}{20}$ – $\dfrac{1}{20}$}$
    $\text{= $\dfrac{99}{20}$}$
    $\text{Vậy A = $\dfrac{99}{20}$}$
    $#Zero#$
    $#Hoidap247#$

  2. Giải đáp:
     99/20
    Lời giải và giải thích chi tiết:
    5/2+5/6+5/12+…+5/9900
    =5(1/2+1/6+1/12+…+1/9900)
    =5(1/1.2+1/2.3+1/3.4+…+1/99.100)
    =5(1-1/2+1/2-1/3+1/3-1/4+…+1/99-1/100)
    =5(1-1/100)
    =5(100/100-1/100)
    =5. 99/100
    =99/20

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