What are some mathematical stories?

1. Mathematics Story - Making Change

A customer came to a cane store and bought a cane for 30 yuan. He took out a 50 yuan note and asked for change.

There happened to be no change in the store, so the shopkeeper went to a neighbor to change the 50 yuan note into change and gave the customer 20 yuan in change.

As soon as the customer left, a neighbor rushed over in a panic, saying that the 50 yuan note was fake. The shop owner had no choice but to pay the neighbor 50 yuan in compensation. Then he went out to chase the customer and caught him and said: "You liar, I will pay 50 yuan to my neighbor and give you 20 yuan in change. You took another cane. You have to compensate me 100 yuan." "Loss."

The customer said: "The cost of a cane is the 30 yuan you left when the neighbor gave you change, so I only took 70 yuan from you."

Please calculate, what is the real loss of the cane store? I should add here that the cost of the cane is 20 yuan. If this customer is successful in defrauding, how much money did *** get from defrauding him?

2. Story: Monkey fishing for hat

A group of monkeys were playing by the well. A gust of wind blew one monkey’s hat into the well. He called 18 friends and came from the well. Fang Zishang went to fish out the hats one by one. Four monkeys did not go up the tree, so they fished out the hats. He asked: How many monkeys went up the tree and went down the well to fish out the hats together?

3. Story: When did the snail climb up the well?

A snail accidentally fell into a dry well. It lay on the bottom of the well and cried. A toad came over and said angrily to the snail: "Stop crying, little brother." , There is no point in crying, the wall of this well is high and slippery, I can only live here if I fall here. I have lived here for many years. The snail looked at the old and ugly toad and thought to himself: "Outside the well." What a beautiful world! I would never live like that in a dark, cold well. The snail said to the toad, "Uncle Legg, I can't live here. I have to climb out. How deep is this well?" "Hahaha... What a joke. This well is 10 meters deep. You are so young." How could he climb out with such a heavy shell on his back? "I'm not afraid of hardship or tiredness. If I climb a little bit every day, I can always climb out!" "The next day, the snail was full and started to climb up the well wall. It kept crawling and crawling. In the evening, it finally climbed 5 meters. The snail was very happy and thought: "Like this Speed, I can crawl out tomorrow evening. "Thinking about it, he fell asleep unknowingly. In the morning, the snail was woken up by a burst of snoring. When he saw it, it turned out to be the leprous uncle who was still sleeping. He was shocked: "Why am I so close to the bottom of the well? "It turned out that after the snail fell asleep, it slid down 4 meters from the well wall. The snail sighed, gritted its teeth, and started to climb up again. In the evening, it climbed another 5 meters, but at night, the snail slid down again 4 meters. Mi, just like this, crawling and sliding, finally the strong snail climbed up to the well platform. Smart children, can you guess how many days it took the snail to climb up the well platform?