The qualified rate of a batch of products is 98%. If there are 400 products in this batch, how many unqualified products are there?
一批产品的合格率是98%，如果这批产品共有400个，那么不合格的产品有多少个．
<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">400 * (1/50)</gadget>
<output>8</output>

<result>8</result>