London, England, the venue of this year's International Mathematics Olympiad.

In the past few days, teams from more than 100 countries around the world have arrived in London.

There is an eight-hour time difference between GMT and the time in the Chinese capital, and the Chinese Olympiad national team arrived in London three days early, reserving the time to reverse the jet lag.

The British organisers arranged for the Chinese Olympiad team to stay in a hotel near Waterloo Station, a 10-minute walk from London's South Bank University.

The leader, deputy leader, coach, translator, logistician and six members of the Chinese Olympiad team are satisfied with the accommodation arrangement, the hotel is not luxurious but clean and comfortable, and it is also close to London South Bank University, the venue of the IMO competition.

Shen Qi and Zhou Yu lived in a room, and they both persevered to the end and were selected for the official list of six members of the Chinese Olympiad team.

The two young men of the same age were full of energy, this was their first time in the UK, so they didn't want to get jet lag, so they put their luggage in the hotel, and Shen Qi and Zhou Yu'an went out to play together.

Of course, they didn't dare to go too far, and they walked around the hotel, with a radius of no more than 3 miles.

As soon as he walked out of the hotel gate, Shen Qi found something that shocked him.

"Hey, Zhou Yu'an, look here, my English level is average, but I know all the English on this brand, if I'm not mistaken, their strawberries can't sell even a box. Shen Qi stopped in front of a supermarket on Waterloo Street.

A sign on the front of the Tesco supermarket reads, "Today's Deal, Strawberries 1 lb/box, 3 lb/2 boxes." ”

Zhou Yu'an's English is good, he quickly understood the preferential information, thought about it and said: "Maybe the British use a mysterious and special number system, 1 is directly followed by 3, and there is no 2." ”

"Hehe, Zhou Yu'an, you poked my laughter, I would rather believe that this is a clerical error, go, go into the supermarket and take a look. Shen Qi pulled Zhou Yu'an into the supermarket together.

After walking around the supermarket for a few minutes, Shen Qi keenly found that "strawberries 1 pound/box, 3 pounds/two boxes" did not look like a clerical error by the supermarket promotion manager.

There is a shelf stocked with chocolate products, among which Hershey's chocolates are on sale, and the supermarket promotion is: "HEYSHEY'S - 30%-off, £18.5."

"Hey, Zhou Yu'an, look, Hershey's chocolate was originally priced at £15 a box, and 30%-off means 7% off, so the discount price should be £10.5 per box, and what the hell is this £18.5?" Shen Qi fell into deep thought.

Zhou Yu'an thought for a while and said: "This store wants to close its doors and refuse customers to leave the door?"

Looking at the endless stream of local customers coming and going, Shen Qi shook his head: "However, this is not the case, you see, this supermarket has a lot of customers, and it can be said that business is booming." I'm also surprised, there are really customers who buy strawberries and Hershey, and there are quite a few!"

Zhou Yu'an carefully observed a cash register not far away, "1 pound/box, 3 pounds/two boxes" of promotional strawberries, a British sister bought 8 boxes in one go, she was very happy, as if she had picked up a big bargain.

After the British eldest sister finished paying, a blonde guy put 4 boxes of Hershey's chocolates on the cash register, laughing hehehehe, the sun was shining.

Shen Qi and Zhou Yu'an looked at each other and were speechless.

"I'm just afraid...... The inhabitants of this area are all fools, right?" Shen Qi deduced this hypothesis.

"Obviously, it's a black shop, and the customers are fools. Zhou Yu'an nodded, agreeing with Shen Qi's assumption.

"London, the capital of finance, the capital of fashion, the capital of football, the capital of silly hats?" Shen Qi further deduced the second hypothesis.

"It is also possible that the people of London are generally wealthy, after all, it is the capital of the empire on which the sun never sets, and it is understandable that people are stupid and have a lot of money. On the basis of Shen Qi, Zhou Yu'an added a supplementary hypothesis.

"Mathematics Olympiad, the Olympics in mathematics, the intellectual competition of high-IQ people, Zhou Yu'an, why do you want to arrange it to be held in the capital of stupid hats?"

"Maybe it's to highlight ...... Contrasting cute?"

The two Chinese young men paced among a group of whites, blacks, and Indians, and felt that the world was so big that it was worth the trip to come out and see for a long time.

"Zhou Yu'an, I'm here, I can't go back empty-handed, buy something, after all, it's produced in the UK. Shen Qi picked up a shopping basket, stopped and stopped, and took some snacks on the shelf.

Zhou Yu'an was more frugal, so he bought a toothpaste and held it directly in his hand: "When I entered the customs, my Chinese toothpaste was confiscated by the British as a dangerous biochemical, and I had to buy a toothpaste to deal with it for a few days." ”

"Give me the toothpaste, and I'll pay for it. Shen Qi took the toothpaste in Zhou Yu'an's hand and put it in his basket.

In front of the cash register, Shen Qi and Zhou Yu'an waited to pay.

A few minutes later, the two came to the cashier, and Shen Qi put his shopping basket on the cash register.

"Hello. The cashier girl said in English that she was a young white red-haired girl.

"Hmm. Shen Qi nodded and did not speak.

The cashier girl took out one item after another from the shopping basket, scanned the code, and the total amount was displayed on the cash register: 33.50 pounds.

"£33 for 50pence. The cashier girl said to Shen Qi.

"Walter?" Shen Qi was puzzled.

"£33...... 50p. The cashier girl repeated, speaking slowly.

Shen Qi said to Zhou Yu'an: "I bought a box of biscuits for £5.8, a muffin for £4.6, three doughnuts for £5.4, and five packets of potato chips. The unit price of each pack of potato chips is £2, buy five packs and enjoy a 20% discount, plus Zhou Yu'an's toothpaste is £2.2, plus the 7% GST here, I should pay £27.82 for our consumption, not £33.50, which is not a result of 33.50. ”

"That's right, it's 27 pounds and 82 pence indeed. Zhou Yu'an also calculated the total amount in a short period of time.

"Hey, young gentlemen, do you need these goods?" The cashier girl saw that Shen Qi and Zhou Yu'an were chatting for a long time, and she couldn't understand Chinese, so she reminded her and kept enough patience.

"Sorry. Shen Qi said apologetically to the cashier girl, and then said to Zhou Yu'an: "Your spoken English is more than 6, you tell this red-haired young lady the consumption details I just said and translate them into English." ”

“OK。 Zhou Yu'an nodded and said to the cashier girl in English: "This lady, I think you miscalculated our consumption amount." ”

The cashier girl shook her head resolutely: "Impossible, this is the result of computer calculations." ”

Zhou Yu'an reported the details in one breath, and he spoke English very fluently: "A box of biscuits is £5.8, a muffin is £4.6, three doughnuts are £5.4, a toothpaste is £2.2, five packets of potato chips are 20% off, and the subtotal is £8, and counting the 7% GST, we have to pay a total of £27 and 82p, which we think is a reasonable and correct amount." ”

The cashier girl was instantly stunned: "You...... What are you talking about?"

Zhou Yu'an was also stunned: "I speak English, don't you understand?"