Check 100 parts, the pass rate is 90%, how many parts are unqualified.
查验100个零件，合格率为90%，不合格的零件个数有多少个．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 - (9/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">100 * (1/10)</gadget>
<output>10</output>

<result>10</result>