There is a pile of steel pipes on the construction site. The cross section is a trapezoid. It is known that there are 2 steel pipes on the top layer and 10 steel pipes on the bottom layer. How many steel pipes are there in total in this pile?
工地上有一堆钢管，横截面是一个梯形，已知最上面一层有2根，最下面一层有10根，这堆钢管共有多少根．
<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>