If you record 100 meters eastward along a straight line as +100 meters, and 200 meters westward as -200 meters, then Zhang Lin first walks 150 meters eastward, and then walks 200 meters westward along the original road, the result should be recorded as how many meters ．
如果把沿直线向东走100米来记作+100米，向西走200米记作-200米，那么张琳先向东走150米，然后沿原路向西走200米，结果应记作多少米．
<gadget id="calculator">200 - 150</gadget>
<output>50</output>

<result>50</result>