A piece of wood is 12m long, if it is sawed into 4 equal lengths, it will take 6 minutes to cut each section, how many minutes will it take in total?
一根木材长12m，把它锯成等长的4段，每锯下一段需要6分钟，一共要花多少分钟．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

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

<result>18</result>