Before, I always thought that learning the knowledge of "finding the least common multiple" was boring, which was similar to "finding the least common multiple of 1 1 and 12" all day. Dealing with people is really annoying. I always feel that learning this knowledge will be useless in my life. However, one thing changed my view.

That was not long ago. Grandpa and I went to the Youth Palace by bus. My father and I took the No.3 bus and were about to leave when the 1 bus just took us away. At this time, grandpa looked at two cars and smiled and said to me, "Xiao Ying, grandpa has a question to test you, okay?" "I answered confidently," OK! " "Then you listen carefully, if the 1 bus comes every 3 minutes, and the No.3 bus comes every 5 minutes. How many minutes will it take for these two cars to start at the same time? " After a pause, I said, "Grandpa, you can't solve this problem. "Grandpa looked puzzled and teased." Really? There is also a premise for this problem: 1 Road and Road 3 start in the same place. After listening to my words, grandpa suddenly patted his bald head with an epiphany and said with a smile, "I am a doctor of mathematics, and sometimes I get confused. My questions are not rigorous enough, but I will still think carefully." Grandpa and I laughed happily. At this moment, Grandpa said, "Well, now suppose that it is the starting point of unification. How do you answer? " "I thought about it and blurted out," 15 minutes. Since 3 and 5 are prime numbers, finding the least common multiple of prime numbers is the product of these two numbers (3х5= 15), so 15 is their least common multiple. In other words, two cars can leave at the same time in at least 15 minutes. Grandpa listened to the boast and teased, "The answer is accurate! 100 points. " "Yes!" After listening to grandpa's words, I raised my hands excitedly.

From this incident, I understand a truth: mathematical knowledge is really everywhere in real life.