It takes 2 minutes to saw a water pipe into two sections, and how many minutes to saw it into five sections.
一根水管锯成两段要2分钟，锯成五段要多少分钟．
<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<gadget id="calculator">2 / 1</gadget>
<output>2</output>

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

<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<result>8</result>