1, 2, 3, 5, 8, 13, 21, 34, 55, ...; How many even numbers are there in the first 100 numbers in this series.
1，2，3，5，8，13，21，34，55，…；这串数的前100个中有多少个偶数．
<gadget id="calculator">100 - 1</gadget>
<output>99</output>

<gadget id="calculator">99 / 3</gadget>
<output>33</output>

<result>33</result>