A bookshelf is divided into three layers: upper, middle, and lower. Originally, the number of books on the upper layer was 16 more than twice that of the middle layer, and there were 80 books on the lower layer. Now take out all the books from the lower layer and place them in the upper and middle layers. Now the upper layer is exactly the middle layer. 2 times. How many books should the lower layer take and put in the middle layer?
一个书架分为上、中、下三层，原来上层书的本数比中层2倍多16本，下层有80本，现将下层书全部拿出分别放入上层和中层，现在上层正好是中层的2倍．下层拿多少本放到中层？
<gadget id="calculator">160 - 16</gadget>
<output>144</output>

<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">144 / 3</gadget>
<output>48</output>

<result>48</result>