On a certain day, the temperature in Beijing is -8**0C～4**0C, what is the temperature difference **0C in Beijing on this day.
某一天，北京气温是-8**0C～4**0C，这一天北京的温差是多少**0C．
<gadget id="calculator">4 - (-8)</gadget>
<output>12</output>

<result>12</result>