Xiao Ming did 20 questions and got 2 wrong. What is the correct rate?
小明做了20道题，错了2道，正确率是多少．
<gadget id="calculator">20 - 2</gadget>
<output>18</output>

<gadget id="calculator">18 / 20</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>