In a pile of steel pipes, there are 2 steel pipes in the uppermost layer and 10 steel pipes in the lowermost layer. The difference between two adjacent layers is 1 steel pipe. How many steel pipes are there in total?
一堆钢管，最上层有2根，最下层有10根，每相邻两层相差1根，一共有多少根．
<gadget id="calculator">2 + 10</gadget>
<output>12</output>

<gadget id="calculator">10 - 2</gadget>
<output>8</output>

<gadget id="calculator">8 + 1</gadget>
<output>9</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">12 * (9/2)</gadget>
<output>54</output>

<result>54</result>