Subtract half of a number, then subtract the remaining (1/3), then subtract the remaining (1/4), ..., then subtract the remaining (1/2009), and finally the remaining 10. This is the original number.
一个数减去它的一半，再减去余下的(1/3)，再减去余下的(1/4)，…，再减去余下的(1/2009)，最后余下10．这个是数原来是多少．
<gadget id="calculator">10 * 2_009</gadget>
<output>20_090</output>

<result>20_090</result>