The mechanical parts factory produces 2,000 parts in the first week of January, of which 1,500 are first-class products, and the rest are second-class products.
机械零件厂一月份第一周产零件2000个，其中一等品1500个，其余为二等品，一等品的个数比二等品多零件总数的几分之几？
<gadget id="calculator">2_000 - 1_500</gadget>
<output>500</output>

<gadget id="calculator">1_500 - 500</gadget>
<output>1_000</output>

<gadget id="calculator">1_000 / 2_000</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>