It takes 12 minutes to saw 4 sections of a piece of wood, how many minutes does it take to saw 7 sections?
锯一块木料，锯4段需12分钟，锯7段需多少分钟．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

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

<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">4 * 6</gadget>
<output>24</output>

<result>24</result>