There are 10 piles of steel, and each pile has 6 pieces of steel on the top layer and 12 pieces on the bottom layer, and there is a difference between each two layers. How many pieces of steel are there in total?
有10堆钢材，每堆钢材最上层有6根，最下层有12根，每两层相差一根，一共有多少根钢材？
<gadget id="calculator">6 + 12</gadget>
<output>18</output>

<gadget id="calculator">12 - 6</gadget>
<output>6</output>

<gadget id="calculator">6 + 1</gadget>
<output>7</output>

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

<gadget id="calculator">18 * (7/2) * 10</gadget>
<output>630</output>

<result>630</result>