Starting from Xiaoming's house, going east is positive, and going west is negative. If Xiao Ming walks 30 meters from home, and then walks -20 meters, how many meters is Xiao Ming's distance from home at this time?
以小明家为起点，向东走为正，向西走为负．如果小明从家走了30米，又走了-20米，这时小明离家的距离是多少米．
<gadget id="calculator">30 + (-20)</gadget>
<output>10</output>

<result>10</result>