A batch of parts, of which 180 are qualified and 20 are unqualified, what is the pass rate of this batch of parts.
一批零件，其中有180个合格，20个不合格，这批零件的合格率是多少．
<gadget id="calculator">180 + 20</gadget>
<output>200</output>

<gadget id="calculator">180 / 200</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">(9/10) * 1</gadget>
<output>9/10 = around 0.9</output>

<result>9/10 = around 0.9</result>