In fact, the allusion to this question is this:
Original title: Zhuge Liang skillfully solved the calculation problem
Soon after Zhuge Liang led the army to camp in Dingjun Mountain, Sima Yi learned that Zhuge Liang had few military forces and prepared to surprise Zhuge Liang's barracks.
One evening, Sima Yi's soldiers will begin to move down from Tiandang Mountain. At this time, Zhuge Shijun was reading Sun Tzu's Art of War under the lamp, and suddenly he came to report that Sima Yi was leading a team to attack the barracks. After hearing this, Zhuge Liang gently shook the feather fan in his hand a few times, stood up, paced back and forth in his tent, and then. Call Guan Xing and Zhang Bao to discuss countermeasures. Zhang Bao said: "The enemy will block you and the water will drown you. You should immediately send troops to fight, and you are willing to fight the Sima thief to the end! " Guan Xing went on to say, "Sima Yi has many soldiers, and we in Serenade are outnumbered. I don't think we can fight to the death! " Zhang Bao said: "Seeing that the fire is about to burn to the brow, what can you do if you don't work hard?" Oshima Geliang then slowly shook the feather fan a few times and said with a smile; "Manpower, think about it, don't have a way. I have a little plan. I wonder if it is feasible? " Guan Yu and others asked urgently, "What's the clever plan? Please tell me quickly! " Zhuge Liang said unhurriedly, "I order you to take three thousand men each, and ambush in front of and behind the mountain during the second watch." Then I thought about a question. As long as the soldiers left behind worked it out overnight, it seems to me that neither Sima Yi nor Sima Yi dared to invade my camp. " Guan Yu said, "Please come up with a plan quickly!" Zhuge Liang gesticulated and said, "There are fifteen pairs of sheep in the house. It is forbidden to slaughter for seven days, but two pairs cannot be slaughtered. How many animals are slaughtered on average every day? There are many rewards for answering correctly. " The second commander listened, like a two-foot-tall monk-scratching his head. It's not convenient to ask again now, so I have to obey.
That night, all the barracks were lit with candles, and the soldiers stayed up all night, calculating the questions given by their teachers.
In the middle of the night, Sima Yi led an army and headed for Dingjun Mountain. He crossed the Han River and looked south. Dingjun Mountain is brightly lit everywhere, just like the shining stars in the sky. Afraid of being caught, he quickly ordered to retreat.
At dawn, the banks of the Han River are safe. General Zhang Guan came to the tent and bowed to Zhuge Liang and said, "The soldiers thought about your problem all night and said," Kill four, four, seven, two, five, seven, thirty-five and five again every day. " Well, it's not right yet! "Zhuge Liang said with a smile," OK, OK! " Zhang Guan first one leng, after thinking for a while, they all burst out laughing.
However, if this problem falls under the title of Olympic Mathematics, there is definitely no solution. If it is a brain teaser, there are too many answers. For example, in the process of slaughter, a ewe suddenly gave birth. . . Or two days later at midnight, after half a pair and half a pair, it is also possible.