There are some water pipes piled up in the warehouse. There are 3 pipes on the first floor, one more pipe on each floor, and 7 pipes on the bottom floor. How many pipes are there in total?
仓库里堆放了一些水管，第一层是3根，以后每层多放一根，最底层7根，这堆水管共多少根．
<gadget id="calculator">3 + 7</gadget>
<output>10</output>

<gadget id="calculator">7 - 3</gadget>
<output>4</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

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

<gadget id="calculator">10 * (5/2)</gadget>
<output>25</output>

<result>25</result>