Xiaoying and Xiaohong set off from school to the library at the same time. Xiaoying's speed was 63 meters per minute. After 12 minutes, Xiaohong was 72 meters behind. What is Xiaohong's speed? (column equation solution)
小英和小红同时从学校出发去图书馆，小英的速度63米/分，12分钟后，小红落后72米．小红的速度是多少？(列方程解答)
<gadget id="calculator">63 * 12</gadget>
<output>756</output>

<gadget id="calculator">756 - 72</gadget>
<output>684</output>

<gadget id="calculator">684 / 12</gadget>
<output>57</output>

<result>57</result>