If it takes 3 minutes to saw a piece of wood into 5 equal sections, how many minutes will it take to complete the sawing?
把一根木头锯成相等的5段，如果每锯一次要3分钟，锯完共需多少分钟．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

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

<result>12</result>