The following series of numbers is an arithmetic sequence: 2, 5, 8, 11, ..., 212. What is the average of this series of numbers.
下面一串数是一个等差数列：2，5，8，11，…，212．这串数的平均数是多少．
<gadget id="calculator">2 + 212</gadget>
<output>214</output>

<gadget id="calculator">214 / 2</gadget>
<output>107</output>

<gadget id="calculator">71 * 107</gadget>
<output>7_597</output>

<gadget id="calculator">7_597 / 71</gadget>
<output>107</output>

<result>107</result>