The talented girl Xu Qingwan asked questions in front of her, and the questions continued, and Su Chen gradually felt that her head was getting bigger.

As the saying goes: a woman's lack of talent is virtue, the ancients had an opinion on women's reading, thinking that women read more, have more ideas, and have more scheming, and are not easy to be at the mercy of men's arbitrariness, well-behaved and obedient, and official schools and private schools are to suppress women's reading.

Only the families of powerful and wealthy businessmen will think of letting the daughter of the house know the truth, because marrying into the right family of the powerful family, some culture and thinking, in addition to managing the big family, can live longer.

Because as soon as she enters the Houmen, she is as deep as the sea, and brainless women who do not read and have no culture are often short-sighted and open-mouthed, and it is easy to die in a wealthy family.

But Su Chen's current idea is that if Xu Qingwan didn't read so many books, he wouldn't be so troublesome at this time, explaining many problems to her.

As soon as she got through the poetry essay, Xu Qingwan picked up a piece of paper full of Arabic numerals and calculation formulas, and asked again with a studious question.

Xu Qingwan looked at it curiously for a few times, and some couldn't understand the strange symbols on it, and she had never seen it, and asked, "What are these symbols?" Is it useful? ”

Su Chen nodded slightly and said: "These symbols represent numbers, such as the mathematical characters we use in our daily life, one, two, three, etc., I used 1, 2, and 3 instead, so that the calculation is very simple, and there is no need to have a complex ...... of cumulative operation."

So, Su Chen explained the words he had explained to Bai Susu to Xu Qingwan again. After a long time, the beauty's small lips opened into an O-shape, and she was a little stunned at this moment.

Su Chen wrote down the number of ten and hundred digits on the paper, and after carefully explaining, Xu Qingwan's eyes became brighter and brighter, flashing with wisdom, and she kept nodding her head, with these numbers instead of traditional characters, the calculation is very simple, and the calculation will naturally reduce suffering.

Through contact and communication, Su Chen found that Xu Qingwan was also very accomplished and interested in mathematics, so he made an exception to explain more to Xu Cainu, from binary, ternary, simple multiplication and division and xy equations, etc., to complex open squares, open squares, sine, antichord numbers, and mathematical knowledge from elementary school to junior high school, the morning passed like this.

After her mouth was dry, what surprised Su Chen was that Xu Cainu's receptivity seemed to be surprisingly high, in other words, this was a female scholar!

"These calculations are so convenient and amazing."

Xu Qingwan sighed lightly, as if she had discovered a new continent, her eyes were full of light, and she was surprised, as if she had found another thing to study besides poetry.

At this time, Su Chen thought that she could come up with some questions and let Xu Cainu calculate, so that she could stop for a while.

"Miss Xu, for example, if I come up with a few simple questions, you can calculate how to do it here, and you can also use these formulas." Su Chen proposed.

Xu Qingwan heard that the other party was going to teach herself, nodded her head, and said with a smile: "When you just start using it, you still need to adapt to it for a while to change your thinking, you can't deliberately make problems and embarrass others." ”

"It's not a problem." Su Chen smiled, and then asked: "Chickens and rabbits have a total of one hundred feet, if you replace chickens with rabbits and rabbits with chickens, there will be a total of ninety-two feet." How many chickens and rabbits are there?"

Xu Qingwan was stunned for a moment, listening to such a topic, she couldn't laugh or cry, she used to be a pair of pairs, doing poetry, and now she is accounting for chickens and rabbit feet.

If it was done before, such a calculation would have taken some effort and thinking, but after having the xy formula, Xu Cainu drew inferences from one another, used equations and Arabic numerals, calculated it on paper, and in an instant, she came to a conclusion.

"Fourteen chickens and eighteen rabbits, yes or no?" Xu Qingwan looked at Su Chen with light eyes and asked.

Su Chen nodded slightly, looking at the calculation formula on her manuscript paper, there was no mistake, and it was very correct to come up with such an answer.

"Okay, then listen to this question again, there is a flock of chickens and rabbits, and the total number of legs is more than twice the total number of heads, eighteen, how many rabbits are there?"

After Xu Qingwan listened, she immediately started to write, listed the equations on the white paper, and after a while, she looked up and said, "Nine rabbits!" ”

Su Chen exclaimed: "Not bad, I didn't expect you to be so strong in learning." ”

Xu Qingwan smiled lightly and said, "Thanks to this calculation formula and computational thinking!" ”

Su Chen asked the question again: "Listen to it again, there are a total of 100 chickens and rabbits, and the chicken's feet are 80 more than the rabbit's feet......"

Xu Qingwan interrupted the question at this time and said, "Master Su, can we stop counting chickens and rabbits all the time, and change to another animal." ”

Su Chen smiled slightly and said, "Okay, since that's the case, let's change a few animals and increase the difficulty!" Yes, the spider has eight legs, the dragonfly has six legs and two pairs of wings, and Chan has six legs and one pair of wings, and now there are eighteen of these three animals, one hundred and eighteen legs and twenty pairs of wings, how many of each small animal?"

Xu Qingwan frowned lightly, she could hear that the problem was a little difficult this time, she began to patiently write the formula on the paper, and then calculate the number of their respective animals, as long as there is mathematical thinking, the seemingly difficult problem actually has a good formula for solving the problem, and it is not difficult to calculate in the end.

After a while, Xu Qingwan's eyes flashed and said, "There are five spiders, seven dragonflies, and six cicadas, right?" ”

Su Chen looked at the appearance of Xu Dacai's talented woman and her diligent study, and already understood that the arithmetic problems in elementary school were difficult for her.

Don't look at Xu Qingwan, it's just the first day to dismantle these numbers and formulas, but she learns very fast thinking, has strong mathematical ability, and is both skilled in starting and quickly comprehending. If this was in his time, she would have been a talented woman from Peking University, and she would have studied for a bachelor's, master's and doctor's degree.

"Okay, let's calculate this today, you go back and get familiar with it!" Su Chen was worried that he would hook up this Nizi's interest in mathematics, so it would be bad to come to him every day to do problems, so it would be too much.

Xu Qingwan was indeed unsatisfied, looked at him with a smile, and said: "I didn't expect you to know so many wonderful ideas, simple and convenient, but it contains truth, I thought that Su Gongzi was only good at poetry and writing, it turned out that even arithmetic was so proficient, and I should ask Su Gongzi for advice in the future." ”

When Su Chen heard this, he complained bitterly, being targeted by a female student bully would be enough for him to have a headache in the future.

"Actually, poetry and arithmetic are all on paper, but my favorite is Gewu, didn't you still doubt the usefulness of Gewu at the banquet yesterday? I'm going to take you to see if it can really benefit the people. After Su Chen finished speaking, he took Xu Qingwan out of the study and sat on the wooden table and bamboo chair in the courtyard.

There are also several equipment for filtering fine salt that he put aside on the table, and Su Chen took some coarse salt, which are all large pieces of salt that people can buy on the market, which contain a lot of mineral impurities, and will have a dry, sour and bitter taste when eaten, and long-term use will also cause some damage to people's bodies.

Xu Qingwan asked curiously, "What are these for?" ”

Su Chen explained: "To make fine salt, you can also add iodine, and eat my Su Ji's fine iodized salt in the future, which can allow the people to reduce diseases and enhance their physique from the aspect of eating, and the average age of the people in the Tang Kingdom will live at least five more years!" ”

Xu Qingwan's eyes showed a look of surprise, obviously a little incredulous, and said suspiciously: "Is this really the effect?" ”

"That's, there's nothing you can't do, only you can't think of it, you just see!" After the words fell, Su Chen began to concentrate on production, starting from the steps of dissolution, precipitation, filtration, and evaporation.