Lin Jing's home is 3.4 kilometers away from the library. When she went to the library at noon, she walked 0.5 kilometers away from home and returned home to get a library card. This time she walked how many kilometers more than usual.
林静家距离图书馆3.4千米，中午去图书馆时，走到离家0.5千米时又返回家拿借书卡，这次她比平时多走了多少千米．
<gadget id="calculator">0.5 * 2</gadget>
<output>1</output>

<result>1</result>