A bookshelf has upper and lower floors, 80 books on the upper floor and 190 books on the lower floor. If the ratio of books between the upper and lower floors is 5:4, how many books should be distributed from the lower floor to the upper floor?
一个书架有上下两层，上层有书80本，下层有书190本，现要使上、下两层书的本书比为5：4，应从下层分几本放到上层？
<gadget id="calculator">80 + 190</gadget>
<output>270</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">270 * (4/9)</gadget>
<output>120</output>

<gadget id="calculator">190 - 120</gadget>
<output>70</output>

<result>70</result>