There is a distance of 2 kilometers from home to school. When Xiao Ming walks 0.5 kilometers from home to school, he finds that he forgot his math books at home and immediately returns home to get the math books. How many kilometers did Xiao Ming walk from school to home today?
从家到学校有2千米的路程，小明从家到学校，走到0.5千米时，发现数学书忘在家里，立即返回家拿数学书．下午正常放学回家，小明今天上学到放学回家共走了多少千米？
<gadget id="calculator">0.5 * 2</gadget>
<output>1</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<result>5</result>