If a piece of wood of uniform thickness takes 12 minutes to saw into 4 pieces, how many minutes will it take to saw it into 5 pieces?
一段粗细均匀的木头，锯成4段需要12分钟，锯成5段用多少分钟．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">12 / 3</gadget>
<output>4</output>

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

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<result>16</result>