There are 9 logs at the bottom of a pile of wood, the difference between every two adjacent layers is 1 log, and the top layer is 2 logs. How many logs are there in total in this pile?
一堆木材最底层是9根，每相邻两层相差1根，最上层是2根，这堆木材一共有多少根？
<gadget id="calculator">2 + 9</gadget>
<output>11</output>

<gadget id="calculator">9 - 2</gadget>
<output>7</output>

<gadget id="calculator">7 / 1</gadget>
<output>7</output>

<gadget id="calculator">7 + 1</gadget>
<output>8</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">11 * 4</gadget>
<output>44</output>

<result>44</result>