If it takes 12 minutes to saw a piece of wood into 4 sections, how much time will it take to saw this piece of wood into 5 sections at the same speed?
如果把一根木料锯成4段要用12分，那么用同样的速度把这根木料锯成5段，要用多少．
<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>