On April 2, 2011, the highest temperature in a certain place is 18°C, and the lowest temperature is -3°C, what is the temperature difference in this place?
2011年4月2日，某地的最高气温是18℃，最低气温是-3℃，那么该地的温差是多少℃．
<gadget id="calculator">18 - (-3)</gadget>
<output>21</output>

<result>21</result>