Dad has to walk 2.4 kilometers from home to work. After he walked 0.5 kilometers, he found that he forgot to take a document, so he went home to pick up the documents. How much more kilometers would he have to walk to go to work than usual?
爸爸从家到单位要走2.4千米，他走了0.5千米后发现有一份文件忘了拿，于是又回家取文件，这样他比平时上班要多走多少千米？
<gadget id="calculator">0.5 * 2</gadget>
<output>1</output>

<result>1</result>