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bài toán lớp 5 mà quên cách giải.

Thảo luận trong 'Số học' bắt đầu bởi van19893, 21 Tháng chín 2012.

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  1. van19893

    van19893 Guest


  2. Đề sai hả bạn?
    Dạng này ko có quy luật sao tính dc?
    ---------------------------------------------->?
     
  3. doreamonhihi

    doreamonhihi Guest


    Bài này hình như có vấn đề thật. Hình như sai ở phần khoảng cách. Phân số thứ nhất có khoảng cách là 3 đơn vị ở phần mẫu số trong phép tính, phân số thứ hai có khoảng cách là 4 đơn vị ở phần mẫu số trong phép tính và cuối cùng thì lại có khoảng cách 3 đơn vị.
     

  4. tinh nhanh
    1/2+3 -1/3+4-1/4+5-.....1/99+100
    llllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllooooooooôoooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo
     
  5. zonedongha

    zonedongha Guest


    hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhho=>:)>-:)>-o-+@};-@-)
     

  6. A=1/4 + 1/(4x7) + 1/(7x11)+ 1/(11x14) +....+ 1/(28x31).
    =1/4+1/4-1/7+1/7-1/11+1/11-1/14+.....+1/28-1/31
    sau đó ta bỏ các phân số giông nhau
    =1/31
     

  7. A=1/4 + 1/(4x7) + 1/(7x11)+ 1/(11x14) +....+ 1/(28x31).
    =1/4+1/4-1/7+1/7-1/11+1/11-1/14+.....+1/28-1/31
    sau đó ta bỏ các phân số giông nhau
    =1/31