There are 15 pieces of wood in the bottom layer of a pile, 1 piece less than the bottom layer in the upper layer, and 10 pieces in the top layer. How many pieces of wood are there in this pile?
一堆木料最下层15根，上一层比下一层少1根，最上层10根，这堆木料多少根？
<gadget id="calculator">15 + 10</gadget>
<output>25</output>

<gadget id="calculator">15 - 10</gadget>
<output>5</output>

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

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">25 * 3</gadget>
<output>75</output>

<result>75</result>