The temperature for one day in Mount Emei this winter is -9°C to 2°C, what is the temperature difference in this day in Mount Emei?
今冬峨眉山有一天的气温是-9℃～2℃，峨眉山这一天的温差是多少℃．
<gadget id="calculator">2 - (-9)</gadget>
<output>11</output>

<result>11</result>