A person hikes 38 kilometers a day on flat roads and 23 kilometers a day on mountain roads. He walks a total of 450 kilometers in 15 days. Question: How many kilometers of mountain roads did he walk during this period?
某人徒步旅行，平路每天走38千米，山路每天走23千米，他15天共走了450千米．问：这期间他走了多少千米山路？
<gadget id="calculator">23 * 15</gadget>
<output>345</output>

<gadget id="calculator">450 - 345</gadget>
<output>105</output>

<gadget id="calculator">38 - 23</gadget>
<output>15</output>

<gadget id="calculator">105 / 15</gadget>
<output>7</output>

<gadget id="calculator">15 - 7</gadget>
<output>8</output>

<gadget id="calculator">8 * 23</gadget>
<output>184</output>

<result>184</result>