The qualified rate of a textile is 98%. Among 500 products, how many are unqualified.
一种纺织品的合格率是98%，500件产品中，不合格的有多少件．
<gadget id="calculator">98 / 100</gadget>
<output>49/50 = around 0.98</output>

<gadget id="calculator">1 - (49/50)</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">500 * (1/50)</gadget>
<output>10</output>

<result>10</result>