After a batch of parts is inspected, the ratio of the number of qualified parts to non-conforming parts is 1:4. What is the pass rate of this batch of parts?
一批零件经检验，合格零件与不合零件的个数比是1：4，这批零件的合格率是多少．
<gadget id="calculator">4 / 1</gadget>
<output>4</output>

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">(1/5) * 1</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>