The fresh-keeping temperature of Mr. Wang’s refrigerator is 4°C above zero, and the temperature in the freezer is 18°C below zero. What is the difference between the two room temperatures in °C? ．
王老师家的冰箱保鲜温度为零上4℃，冷冻室的温度为零下18℃，两室温差是多少℃．．
<gadget id="calculator">4 - (-18)</gadget>
<output>22</output>

<result>22</result>