A five-story building has a total height of 15 meters. Xiaodong lives on the fourth floor. How high does he have to climb once he enters the room from downstairs?
一幢五楼的大厦总高15米，小冬家住4楼，他从楼下进房一次要爬多高？
<gadget id="calculator">15 / 5</gadget>
<output>3</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<result>9</result>