It takes 18 minutes to saw a piece of wood into 4 sections, how long does it take to saw all of them?
把一根木料锯成4段，每锯一次需要18分钟，全部锯完需要多长时间？
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">18 * 3</gadget>
<output>54</output>

<result>54</result>