There is a pile of steel pipes on the construction site. The cross section is a trapezoid. It is known that there are 3 steel pipes in the top layer and 10 steel pipes in the bottom layer. There are 8 layers in total. How many steel pipes are there 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3根，最下面一层有10根，共堆了8层，这堆钢管共有多少根．
<gadget id="calculator">3 + 10</gadget>
<output>13</output>

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

<gadget id="calculator">13 * 4</gadget>
<output>52</output>

<result>52</result>