In a pile of wood, there are 2 pieces on the top floor, 6 pieces on the bottom floor, and there is a difference between two adjacent floors. How many pieces of wood are there in total in this pile?
一堆木料，最上层有2根，最下层有6根，相邻的两层都相差一根，这堆木料共有多少根
<gadget id="calculator">6 + 2</gadget>
<output>8</output>

<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">8 * (5/2)</gadget>
<output>20</output>

<result>20</result>