On February 27, the weather forecast column in Beijing showed that the temperature was -2°C to 4°C. What is the temperature difference (that is, the difference between the highest temperature and the lowest temperature) of the day?
2月27日，北京的天气预报栏上显示，气温为-2℃～4℃．当天的温差(即最高气温与最低气温相差)是多少℃．
<gadget id="calculator">4 - (-2)</gadget>
<output>6</output>

<result>6</result>