Xiao Ma goes to school from home in the morning, and his home is 1.56 kilometers away from school. After he walked 0.17 kilometers, he found that he did not bring a math book, so he went home to get it. How many kilometers did he walk to school in total?
小马早上从家去学校，家离学校1.56千米，他走了0.17千米后发现没有带数学书，又回家去拿，这样他到学校一共走了多少千米？
<gadget id="calculator">0.17 * 2</gadget>
<output>0.34</output>

<gadget id="calculator">0.34 + 1.56</gadget>
<output>1.9</output>

<result>1.9</result>