A building has 25 floors above ground and 4 floors below ground. If the floor above the ground is recorded as a positive number, the height of each floor of the building is 3 meters, how many meters does it rise by taking the elevator from the -2 floor to the +8 floor.
一幢大楼，地面以上有25层，地面以下有4层．如果地面以上的楼层记为正数，大楼的每层高度是3米，从-2层坐电梯到+8层，上升了多少米．
<gadget id="calculator">8 - (-2)</gadget>
<output>10</output>

<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<result>30</result>