There are 10 true or false questions in an intelligence test, 3 points are awarded for each correct answer, and 2 points are deducted for each incorrect answer. Xiaoli finished answering 10 questions and only got 10 points. How many questions did she get wrong?
一次智力测验有10道判断题，每答对一道得3分，每答错一道扣2分．小丽答完了10道题，只得10分．她答错了多少题．
<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<gadget id="calculator">30 - 10</gadget>
<output>20</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">20 / 5</gadget>
<output>4</output>

<result>4</result>