If it takes 6 minutes to saw a piece of wood into 3 pieces, how many minutes will it take to saw it into 7 pieces?
把一根木料锯成3段需要6分钟，锯成7段需要多少分钟．
<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

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

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

<result>18</result>