Students do exercises, plan to have 20 people in each row, and you can stand in 18 rows. If there are 4 more people per row than planned, how many rows can you stand? (Solve with ratio)
同学们做操，计划每行20人，可以站18行．如果每行比计划多站4人，可以站多少行？(用比例解)
<gadget id="calculator">18 * 20</gadget>
<output>360</output>

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

<gadget id="calculator">360 / 24</gadget>
<output>15</output>

<result>15</result>