When Xiao Ming visited the steel factory, he saw many steel pipes piled up in a trapezoidal shape. He counted 8 steel pipes on the top layer and 14 steel pipes on the bottom layer. There are 7 layers in total. How many steel pipes are there in this pile?
小明参观钢铁厂时看到许多钢管堆成梯形状，他数了最上层有8根，最下层有14根，一共有7层，这堆钢管一共有多少根？
<gadget id="calculator">8 + 14</gadget>
<output>22</output>

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

<gadget id="calculator">22 * (7/2)</gadget>
<output>77</output>

<result>77</result>