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

Toán Lớp 7: `/16 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 + 1/72 + 1/90` Nhanh nhé để mình nộp cho cô

Tháng Bảy 17, 2022 Toán học 2 Comments 0 views

Toán Lớp 7: /16 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 + 1/72 + 1/90
Nhanh nhé để mình nộp cho cô

Comments ( 2 )

  1. thaolanphuobg
    thaolanphuobg
    17 Tháng Bảy, 2022 at 2:05 chiều
    Reply
    ~ Muối gửi bài ạ :
     1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 + 1/72 + 1/90 
    => 1/(2xx3) + 1/(3xx4) + 1/(4xx5) + 1/(5xx6) + 1/(6xx7) + 1/(7xx8) + 1/(8xx9) + 1/(9xx10)
    => 1/1 – 1/2 + 1/2 – 1/3 + 1/3 – 1/4 + 1/4 – 1/5 + 1/5 – 1/6 + 1/6 – 1/7 + 1/7 – 1/8 + 1/8 – 1/9 + 1/9 – 1/9 + 1/10 
    => 1/1 – 1/10 ( Gạch bỏ những cái giống nhau )
    => 1 – 1/10 
    => 10/10 – 1/10
    => 9/10 .
    ~ Xin hay nhất ạ ~

  2. ngocbichchau
    ngocbichchau
    17 Tháng Bảy, 2022 at 2:05 chiều
    Reply
    1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/57 + 1/72 + 1/90
    = 1/(2. 3) + 1/(3 . 4) + 1/(4 . 5) + 1/(5 . 6) + 1/(6 . 7) + 1/(7 . 8) + 1/(8 . 9) + 1/(9 . 10)
    = 1/1 – 1/2 + 1/2 – 1/3 + 1/3 – 1/4 + 1/4 – 1/5 + 1/5 – 1/6 + 1/6 – 1/7 + 1/7 – 1/8 + 1/8 – 1/9 + 1/9 – 1/10  
    = 1/1 – (1/2 – 1/2) – (1/3 – 1/3) – (1/4 – 1/4) – (1/5 – 1/5) – (1/6 – 1/6) – (1/7 – 1/7) – (1/8 – 1/8) – (1/9 – 1/9) – 1/10
    = 1/1 – 1/10  
    = 9/10

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

Khánh Ly

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