There is a column of numbers: 1, 2, 3, 5, 8, ..... What is the 10th number in this column.
有一列数：1、2、3、5、8、…..这列数中第10个数是多少．
<gadget id="calculator">5 + 8</gadget>
<output>13</output>

<gadget id="calculator">8 + 13</gadget>
<output>21</output>

<gadget id="calculator">13 + 21</gadget>
<output>34</output>

<gadget id="calculator">21 + 34</gadget>
<output>55</output>

<gadget id="calculator">34 + 55</gadget>
<output>89</output>

<result>89</result>