It takes 18 minutes to saw a piece of wood into four pieces, how many minutes will it take to saw it into five pieces?
一根木材，锯成四段需18分钟，如果要锯成五段需多少分钟．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

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

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

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

<result>24</result>