Wenwen did 10 questions in the morning, 9 of which were correct; he did 10 more questions in the afternoon, and got 1 of them wrong. What is the correct rate of doing the questions on this day?
文文上午做了10道题，对了9道；下午又做了10道题，错了一道．这一天做题的正确率是多少？
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">9 + 9</gadget>
<output>18</output>

<gadget id="calculator">10 + 10</gadget>
<output>20</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>