We record "+" above sea level and "-" below sea level. The altitude of place A is 40 meters, the altitude of place B is 25 meters, and the altitude of place C is -20 meters. Which place is the highest? Where is the lowest? How much higher is the highest place than the lowest place?
我们把高出海平面记作"+"，低于海平面记作"-"，甲地海拔高度是40米，乙地海拔高度是25米，丙地海拔高度是-20米，哪个地方最高？哪个地方最低？最高的地方比最低的地方高多少？
<gadget id="calculator">40 - (-20)</gadget>
<output>60</output>

<result>60</result>