If a pile of coal is transported by 4 vehicles, each vehicle needs to transport 5 tons to finish it. If it is transported by 5 vehicles, how many tons does each vehicle need to transport? (Solution with proportional knowledge)
一堆煤，如果用4辆车来运，每辆车需运5吨才能运完，如果用5辆车来运，每辆车需运几吨？(用比例知识解)
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

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

<result>4</result>