If the indoor temperature is 7°C and the outdoor temperature is -9°C in winter, how much is the indoor temperature higher than the outdoor temperature?
冬天室内温度是7℃，室外温度是-9℃，那么室内温度比室外温度高多少℃．
<gadget id="calculator">7 - (-9)</gadget>
<output>16</output>

<result>16</result>