There are 180 books on the upper shelf, which is three times that of the lower shelf. How many books are there on the two floors?
书架上层有书180本，是下层的3倍，两层一共有多少本？
<gadget id="calculator">180 / 3</gadget>
<output>60</output>

<gadget id="calculator">60 + 180</gadget>
<output>240</output>

<result>240</result>