If it takes 6 minutes to saw a piece of wood into 2 pieces, how many minutes will it take to saw it into 4 pieces?
一根木头锯成2段用6分钟，锯成4段用多少分钟．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

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

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

<gadget id="calculator">3 * 6</gadget>
<output>18</output>

<result>18</result>