There is a pile of engineering waste that needs to be cleaned up. (1/1999) of the total amount was transported for the first time, (2/(1999-1)) of the remaining waste was transported for the second time, and (3/(1999-3)) of the remaining waste was transported for the third time. The remaining (4/(1999-6)) was transported away four times, and the remaining (5/(1999-10)) was transported away for the fifth time. Continue to transport according to this rule, then after transporting 50 times, the remaining waste is the total amount.
现有一堆工程废料需要清理出去．第一次运走总量的(1/1999)，第二次运走余下废料的(2/(1999-1))，第三次运走余下的(3/(1999-3))，第四次运走余下的(4/(1999-6))，第五次运走余下的(5/(1999-10))，依此规律继续运下去，那么当运走50次后，余下废料是总量的多少．
<gadget id="calculator">1_275 / 1_999</gadget>
<output>1_275/1_999 = around 0.637819</output>

<gadget id="calculator">1 - (1_275/1_999)</gadget>
<output>724/1_999 = around 0.362181</output>

<result>724/1_999 = around 0.362181</result>