The students performed group gymnastics. They were originally arranged in 24 rows with 20 people in each row. After the formation changed, they were arranged in 30 rows. How many people were reduced in each row?
同学们表演团体操，原来排成24行，每行有20人，队形变化后，排成30行，每行减少多少人？
<gadget id="calculator">24 / 30</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">20 * (4/5)</gadget>
<output>16</output>

<gadget id="calculator">20 - 16</gadget>
<output>4</output>

<result>4</result>