Zhang Qiang calculated 20 questions and got 1 wrong. What is the correct rate of his calculation this time?
张强口算了20道题，错了1道，他这次口算的正确率是多少．
<gadget id="calculator">20 - 1</gadget>
<output>19</output>

<gadget id="calculator">19 / 20</gadget>
<output>19/20 = around 0.95</output>

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

<gadget id="calculator">(19/20) * 1</gadget>
<output>19/20 = around 0.95</output>

<result>19/20 = around 0.95</result>