There are 10 questions in a knowledge contest, and each question is worth 10 points. 10 points for a correct answer are represented by +10, and 10 points are deducted for a wrong answer, which is represented by -10. How many points.
一次知识竞赛共10题，每题10分，答对一题得10分用+10表示，答错一题扣10分用-10表示，某同学答对了6题，答错了4题，他得了多少分．
<gadget id="calculator">6 * 10</gadget>
<output>60</output>

<gadget id="calculator">4 * 10</gadget>
<output>40</output>

<gadget id="calculator">60 - 40</gadget>
<output>20</output>

<result>20</result>