Xiaogang's home is 500 meters away from the school. After walking 100 meters to school in the morning, Xiaogang found that he didn't bring the book with him, so he hurried home to get it. This morning, how many meters did Xiao Gang walk to school?
小刚的家到学校有500米，早上小刚上学走了100米后，发现书没带，连忙回家取书．这天早上，小刚上学一共走了多少米．
<gadget id="calculator">100 * 2</gadget>
<output>200</output>

<gadget id="calculator">500 + 200</gadget>
<output>700</output>

<result>700</result>