A wooden stick with a length of 2 meters, if it takes 20 minutes to saw a stick with a length of 0.4 meters, how many minutes will it take to saw a stick with a length of 0.5 meters?
一根长2米的木棍，锯成每段长0.4米的木棍需要20分钟，那么锯成每段长0.5米的木棍需要多少分钟
<gadget id="calculator">2 / 0.4</gadget>
<output>5</output>

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

<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">2 / 0.5</gadget>
<output>4</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<result>15</result>