The steel company shipped a batch of steel pipes and piled them up in a trapezoidal shape. It is known that there are 10 roots in the uppermost layer and 20 roots in the lowest layer. There is a difference of 1 root in every two adjacent layers, and there are 11 layers in total. If each steel pipe is worth 500 yuan, how much is this batch of steel pipes worth?
钢材公司运来一批钢管，堆成梯形状．已知最上层有10根，最下层有20根，每相邻两层相差1根，共有11层．如果每根钢管价值500元，这批钢管共值多少元？
<gadget id="calculator">10 + 20</gadget>
<output>30</output>

<gadget id="calculator">11 / 2</gadget>
<output>11/2 = around 5.5</output>

<gadget id="calculator">30 * (11/2) * 500</gadget>
<output>82_500</output>

<result>82_500</result>