Han Xin is a native of Huaiyin, Jiangsu Province. As an outstanding strategist in ancient China, he was not only the representative of China's military thought "Military Tactics", but also the founder of the Western Han Dynasty. He created allusions such as The Last Battle, Crossing Chen Cang, Flying on Houses and so on. Besides, he is also good at math.
At the end of the Qin Dynasty, Chu and Han contended with each other. In one battle, Han Xin led 1500 soldiers to engage with the Chu army, and 1500 soldiers were taken out, but casualties could not be avoided in the battle, so I didn't know how many soldiers were left when I brought them back. As soon as I got back to the camp after the war, I was told that another wave of enemy troops was coming, but the number of enemy troops was almost 500. At this time, Han Xin should work out his remaining forces in a very short time to meet them.
This is how he calculated it. He arranged three soldiers in a row and found two more: Han Xin arranged five soldiers in a row and found three more; Finally, he arranged seven soldiers in a row and found two more. Finally, he calculated that the number of soldiers was 1073. He calculated according to the least common multiple. The least common multiple of 3+2 and 5+3 is 8, and the least common multiple of 3 and 5 is 15, that is, as long as all integers of 8+ 15x meet the conditions, if we divide by 7+2, the least common multiple of 3, 5 and 7 is 655.
The thing about oil distribution is that Han Xin saw two oil sellers on the road and wanted to share 10 kg of oil in the oil drum equally, but there were only three measuring tools at that time, namely, oil drum 10 kg, crock 7 kg and oil gourd 3 kg. Anyway, there was no way to share equally. He let the 3 kg oil gourd be loaded three times in a row, that is, 9 kg in total, and then he poured the oil into a 7 kg crock. At this time, 7 kg is full, 3 kg of oil gourd has 2 kg left, and 10 kg of bucket has 1 kg left. He poured 7 Jin into the 10 Jin barrel, and there were 8 Jin left in the 10 Jin barrel. Then he poured 2 Jin of oil into the crock, and then 3 Jin of oil gourd into the crock. There were 5 Jin in the crock. At this time, the crock and oil drum are 5 kg each, and the average distribution is successful.