There are 4 units in a 35-storey building, and 2 families live in each floor. How many households are there in this building?
一座35层高的楼房共有4个单元，每层住2户人家，这座楼房一共有多少户居民？
<gadget id="calculator">2 * 4 * 35</gadget>
<output>280</output>

<result>280</result>