Scientists found that the number of petals, sepals, fruits and other characteristics of plants are very consistent with a peculiar sequence 1, 1, 2, 3, 5, 8, 13, 21, 34... Observe the above sequence carefully, Then what should be its 11th number?
科学家发现：植物的花瓣、萼片、果实的数目经及其他方面的特征，都非常吻合于一个奇特的数列1，1，2，3，5，8，13，21，34…仔细观察以上数列，则它的第11个数应该是多少．
<gadget id="calculator">21 + 34</gadget>
<output>55</output>

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

<result>89</result>