Xiaoling participated in the mathematics competition. The total number of questions in the paper is 36. The ratio of the number of correct questions to the wrong ones is 7:2. How many questions did Xiao Ling do wrong?
小玲参加数学竞赛，全卷总题数是36题，小玲做对题数与做错题的比是7：2．小玲做错了多少题？
<gadget id="calculator">2 + 7</gadget>
<output>9</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">36 * (2/9)</gadget>
<output>8</output>

<result>8</result>