If above sea level is a positive number, and a submarine rises from 27 meters below sea level to 18 meters below sea level, how many meters does the submarine rise?
若海平面以上为正数，某潜艇从海平面以下27米上升到海平面以下18米，此潜艇上升了多少米？
<gadget id="calculator">27 + 18</gadget>
<output>45</output>

<result>45</result>