Half an hour passed, and Yan Ying, Ji Zha, Sun Ping, and Kong Qiu were unable to solve Qingji's math problem.

Seeing that it was getting late and the sun was setting, Qingji finally shook his head and said the correct answer.

"The final answer is that there are 657 pears and 343 fruits, the price of pears is 803 Wen, and the price of fruits is 196 Wen."

“……”

Hearing this, Yan Ying and the other four were a little confused, and the sons in the school were also confused.

Ji Za asked curiously: "I don't know how the king answered this answer?" ”

"Two or three sons, let's see."

Qingji chuckled, then picked up a piece of chalk and answered it on the blackboard.

The formula for this math problem was densely written on the blackboard by Qing Ji.

It is worth mentioning that the blackboard and chalk are also the first creations of Qingji.

It's different from modern blackboards and chalk, but the effect is the same.

I saw that at this moment, a large list of formulas and words had been listed on the blackboard-

Price per pear: 11÷9=12/9 (text).

Price per fruit: 4÷7=4/7 (text).

Number of fruits:

(12/9x1000-999)÷(12/9-4/7)=343

Number of pears:

1000-343=657

Total price of pears:

12/9x657=803 (text)

Total price of fruit:

4/7x343=196 (text)

"There's another solution."

As soon as the words fell, Qingji began to write on the blackboard again, writing on the board with chalk, listing a set of mathematical formulas.

Solution: Let the pear be x and the fruit be y.

x+y=1000

11/9x+4/7y=999

Solution: x=657;y=343

That is, the number of pears is 657, and the money is: 657*11/9=803

The fruit is 343, and the money is: 343*4/7=196

“……”

Everyone present was stunned.

What is this symbol?

Ghost Drawing?

Qingji, who is a good teacher, saw that everyone was puzzled, and immediately said: "This is a number, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, corresponding to one, two, three, four, Wu, Lu, Qi, 捌, long, pick." ”

"Corresponds to one, two, three, four, five, six, seven, eight, nine, ten."

"Compared with the old numbers, this new type of number is more convenient and suitable for arithmetic."

As he spoke, Qing Ji also erased the mathematical formulas that had been listed on the blackboard, and wrote the corresponding numbers on the blackboard again.

"It's addition, subtraction, multiplication, and division, plus, minus, multiplication, division."

"One plus one equals two, and one plus two equals three."

"Three minus one equals two. Two times two equals four, and vice versa, four divided by two equals two......"

The Arabic numerals of the previous life, as well as addition, subtraction, multiplication and division, and even a simplified version of the ninety-nine multiplication table, were taught to everyone one by one.

This ninety-nine multiplication table actually existed before.

In the famous allusion of "Ting Liao Seeking Talents", after Qi Henggong issued an order to seek talents, he asked people to light a torch in front of the palace, ready to meet talents from all over the world at any time.

However, a whole year passed, and no one came to apply.

At this time, there was a person who claimed to be proficient in the ninety-nine algorithm and boldly visited Qi Henggong......

This is the predecessor of the multiplication mantra - the ninety-nine song.

The original ninety-nine song is from "ninety-nine eighty-one" to "two-two-like four", with a total of 36 sentences.

Because it started from "Ninety-Nine-Eighty-One", it was named Ninety-Nine Song.

In the Spring and Autumn Period and the Warring States Period, not only the decimal system was invented, but also the ninety-nine table was invented.

Greece and Babylon, as ancient countries of Western civilization, also invented multiplication tables, but they are more complicated than ninety-nine tables.

They work so hard to multiply and divide that anyone who can divide a large number is considered a mathematician.

It was not until the beginning of the thirteenth century that the Oriental method of calculation was introduced to Europa through the Arabs, and the Westerners found it convenient and learned this new method.

Therefore, Qingji also had to admire his ancestors.

At least in some areas, the ancestors of China are ahead of the world!

"What kind of symbol is this, King?"

Ji Za pointed to a full stop on the blackboard and asked suspiciously.

"It's a full stop. And commas, exclamation points, ......"

Qingji has the heart to change the status quo.

Because people in this era do not divide symbols when writing, whether they use bamboo slips or paper.

In the face of dense text, without punctuation, it is actually a very painful thing.

Qingji often encounters this kind of problem when he reviews government affairs on weekdays.

Read it slowly, word by word.

Read it again and again, and feel the meaning between the lines over and over again.

But isn't it painful to read it quickly and not read it later?

You know, the production of ancient books is very low, and there are very few types of books that can be found on the market.

However, after Qingji invented papermaking, a large number of books, such as "Shangshu", "Book of Changes", "Book of Songs" and other books were copied and circulated in the market.

Qingji has to deal with some complicated government affairs every day, and there is no punctuation, which is actually a very headache.

After all, this is work for Qingji, not reading books and enjoying life!

Like Kong Qiu, Ji Za and others, they often can't put down the volume, and they can read a book dozens of times, and they can read it well.

They enjoy this kind of reading time, so punctuation is not very useful.

Punctuation also plays a role.

Sometimes the lack of a punctuation mark, i.e., a sentence break, may also misinterpret the meaning of a passage.

"Second and third sons, the widow will give you another question."

Qingji looked at the appearance of everyone who seemed to understand whether they understood or not, and immediately smiled slightly, and wrote a math problem on the blackboard-

Chickens and rabbits are in the same cage I don't know how to count, and thirty-six cages are exposed.

Count 50 pairs of feet, how many chickens and rabbits are there?

This is the famous arithmetic problem in ancient times -

Chickens and rabbits in the same cage!

Compared with the math problem that Qingji came up with before, it can be said to be much simpler.

Qingji is deliberately promoting Arabic numerals, addition, subtraction, multiplication and division, and punctuation.

After a long time, everyone began to answer.

With the addition, subtraction, multiplication and division taught by Qingji and Arabic numerals, everyone present can basically solve it quickly.

However, it is a matter of time, mainly to see whose brain turns faster.

"Father! Erchen has answered! ”

Wu Heng looked excited, took the paper full of formulas in his hand, came to Qingji and said, "The final answer is fourteen rabbits and twenty-two chickens!" ”

"How did you answer that?"

Qingji was quite curious.

Wu Heng hurriedly replied: "If you follow the trick taught by your father, all the rabbits will 'hide' their two feet, that is, thirty-six times two, and seventy-two rabbits will be obtained." ”

"Now there are a hundred feet, so twenty-eight are hidden, and twenty-eight are divided by two, and fourteen rabbits are obtained."

"The number of chickens is easier to derive, thirty-six minus fourteen, that is, there are twenty-two chickens!"

"Good!"

Looking at Wu Heng, who was so witty, Qingji also bowed his head slightly, expressing his approval.

Wu Hong, who was standing not far away, saw this, so he could only silently take back the paper that he had calculated the correct answer.