6 referees score a gymnast, remove the highest score, the average score is 9 points, remove the lowest score, the average score is 9.5 points, how much is the difference between the highest score and the lowest score
6名裁判员给一名体操运动员打分，去掉一个最高分，平均得9分，去掉一个最低分，平均得9.5分，最高分与最低分相差多少分
<gadget id="calculator">9.5 * 5</gadget>
<output>47.5</output>

<gadget id="calculator">9 * 5</gadget>
<output>45</output>

<gadget id="calculator">47.5 - 45</gadget>
<output>2.5</output>

<result>2.5</result>