A 16-storey building is 81 meters high. The lobby on the first floor is 6 meters high. The rest of the floors are all the same height. How many meters are the rest of the floors?
一幢16层的大楼高81米，一楼是大厅层高6米，其余各层层高都相等，其余各层层高多少米？
<gadget id="calculator">81 - 6</gadget>
<output>75</output>

<gadget id="calculator">16 - 1</gadget>
<output>15</output>

<gadget id="calculator">75 / 15</gadget>
<output>5</output>

<result>5</result>