小学奥数简算题~~~(分数),有分赏!~~~

1个回答

  • 1.88888888x88888888分之1+2+3+4+5+6+7+8+7+6+5+4+3+2+1

    =88888888x88888888分之8x8

    =11111111x11111111

    2.(1234+4567×7890)÷(4568×7890-6656)

    =(1234+4567×7890)÷(4568×7890-7890+1234)

    =(1234+4567×7890)÷(4567×7890+1234)

    =1

    3.121121121121/212121212121

    =(121*1001001001)/(21*10101010101)

    =121*12

    =1452

    4.1001-1/2001-2/2001-3/2001-……2001/2001

    =1001-(1/2001+2/2001+3/2001+……+2001/2001)

    =1001-[1/2001×(1+2+3+……+2001)]

    =1001-[1/2001×(1+2001)×2001÷2]

    =1001-[(1+2001)÷2]

    =1001-1001

    =0