There are already 30 boys and 20 girls participating in the sixth grade team competition. For the sake of formation, the number of boys and girls should be changed to 5:4. What should I do?
六年级队列比赛，已经有30名男生和20名女生参加，为了队形需要，想让男、女生人数变为5：4，应该怎么办？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">30 * (4/5)</gadget>
<output>24</output>

<gadget id="calculator">24 - 20</gadget>
<output>4</output>

<result>4</result>