Zhang Ming usually has to walk 1.7 kilometers from home to school. Today, after walking 0.5 kilometers, he found that he forgot his math books, so he hurried home to get them. In this way, Zhang Ming walked from home to school that day. How many kilometers?
张明平时从家去学校要走1.7千米，这天当他走了0.5千米后，发现自己忘带了数学书，赶紧回家去取，这样张明这天从家到学校一共走了多少千米？
<gadget id="calculator">0.5 * 2</gadget>
<output>1</output>

<gadget id="calculator">1.7 + 1</gadget>
<output>2.7</output>

<result>2.7</result>