Some steel pipes are piled up on a construction site. There are 4 steel pipes on the top layer and 40 steel pipes on the bottom layer, and each lower layer has 2 more steel pipes than the upper layer. How many steel pipes are there in total?
某建筑工地堆放着一些钢管，最上面一层有4根，最下面一层有40根，而且下面的每一层比上面的一层多2根，这些钢管一共有多少根？
<gadget id="calculator">40 + 4</gadget>
<output>44</output>

<gadget id="calculator">40 - 4</gadget>
<output>36</output>

<gadget id="calculator">36 / 2</gadget>
<output>18</output>

<gadget id="calculator">18 + 1</gadget>
<output>19</output>

<gadget id="calculator">19 / 2</gadget>
<output>19/2 = around 9.5</output>

<gadget id="calculator">44 * (19/2)</gadget>
<output>418</output>

<result>418</result>