On a certain day, the highest temperature during the day is 12 degrees Celsius, and the lowest temperature at night is -8 degrees Celsius, so what is the maximum temperature difference between day and night in degrees Celsius?
某天白天最高温度是12摄氏度，夜里最低温度是-8摄氏度，那么这天昼夜温差最大达多少摄氏度．
<gadget id="calculator">12 - (-8)</gadget>
<output>20</output>

<result>20</result>