Xiaoxin has to walk 1.5 kilometers from home to school. After he walked 0.3 kilometers, he went home to pick up a book. How much more kilometers would he have to walk to school than usual?
小欣从家到学校要走1.5千米，他走了0.3千米后又回家取了一本书，这样他比平时去学校要多走多少千米？
<gadget id="calculator">0.3 * 2</gadget>
<output>0.6</output>

<result>0.6</result>