A short story in mathematics

A customer of a crutch shop bought a crutch made in 30 yuan. He took out a ticket for 50 yuan and asked for change.

Just as there was no change in the store, the shopkeeper went to the neighbor's house to change the ticket for 50 yuan and gave the customer 20 yuan's change.

Just after the customer left, the neighbors came running in a panic and said that this ticket for 50 yuan was fake. The shopkeeper had to compensate his neighbor 50 yuan. Then I went out to chase the customer, caught him and said, "You liar, I paid 50 yuan, neighbor, and I gave you 20 yuan. You took a crutch, and you have to compensate me 100 yuan. "

The customer said, "The cost of a walking stick is 30 Yuan You left when your neighbor gave you change, so I only took your 70 yuan."

Please calculate, how much is the real loss of the rattan shop? I would like to add here that the cost of crutches is 20 yuan. If this customer succeeds, how much will * * * cheat?

2. Story: The monkey catches the hat.

A group of monkeys are playing by the well. A gust of wind blew a monkey's hat into the well. He called 18' s friends and fished for his hats one by one from the pine trees by the well. Four monkeys don't climb trees, so they go for hats. Q: How many monkeys got their hats from the well under the tree?

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

A snail accidentally fell into a dry well, and it lay down at the bottom of the well and began to cry. A toad came over and said angrily to the snail, "Stop crying, little brother, it's no use crying. This shaft wall is high and slippery, so you can only live here if you fall here. " I have lived here for many years. The snail looked at the old and ugly toad and thought, "What a beautiful world outside the well! I can never live in a dark and cold well like it. " The snail said to the toad, "Uncle toad, I can't live here. I have to climb out. How deep is this well? " "Ha ha ha ..... it's a joke, this well 10 meters deep, you are so young. How can such a heavy shell climb out? " "I am not afraid of suffering, not afraid of being tired. I can always climb out after a while every day! " The next day, the snail was full and began to climb along the wall. It keeps crawling and crawling. At night, it finally climbed 5 meters. The snail was very happy and thought, "At this rate, I can climb out tomorrow night." Thinking about it, I fell asleep unconsciously. In the morning, the snail was awakened by a purr. At first glance, it turned out that Uncle Tu was still sleeping. He was surprised: "Why am I so close to the bottom of the well?" It turned out that this snail fell asleep and slipped down 4 meters from the well wall. The snail sighed, gritted his teeth and began to climb again. At night, it climbed up another 5 meters, but at night, the snail fell down another 4 meters. In this way, it climbed, climbed and slipped, and finally the strong snail climbed onto the well platform. Clever boy, can you guess how many days it took the snail to climb the drilling platform?

References:

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