Master Wang made 100 parts, and the pass rate is 90%. How many parts are unqualified?
王师傅做了100个零件，合格率是90%，不合格的零件有多少个．
<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>