If a person walks 9 meters to the east first and is recorded as +9 meters, then how many meters is the distance from the starting point after the person walks -5 meters.
如果把一个人先向东走9米记作+9米，那么这个人又走-5米后距离出发点有多少米．
<gadget id="calculator">9 + (-5)</gadget>
<output>4</output>

<result>4</result>