One day in February 2010, the temperature in Tianjin was -5°C to 4°C. What is the temperature difference in this day?
2010年2月的一天，天津的气温是-5℃～4℃，这一天的温差是多少℃．
<gadget id="calculator">4 - (-5)</gadget>
<output>9</output>

<result>9</result>