Stack a pile of steel pipes in a trapezoidal shape. There are 10 steel pipes in the top layer and 16 steel pipes in the bottom layer. There are 7 layers in total. How many steel pipes are there in this pile?
把一堆钢管堆成梯形状，最上层有10根，最下层有16根，一共有7层，这堆钢管共有多少根？
<gadget id="calculator">10 + 16</gadget>
<output>26</output>

<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">26 * (7/2)</gadget>
<output>91</output>

<result>91</result>