Prehistoric I was pinched out by Nuwa

It's cool to be distracted for a while, and then listen to the heart.

This multiplication method can be used for multiplication of double-digit numbers and multiplication of three-digit numbers or other multi-digit numbers.

Outside the house, people from Li Yang formed a circle.

The multi-digit multiplication should have been finished the day before yesterday, but it was delayed until today.

Today Li Yang didn't plan to stop, he finished the multiplication in one breath.

In this way, the unless operation can be performed on the next day.

After the basic law of the four arithmetic operations is finished, it should be enough for the clansmen to cope with the current situation.

As for coping with the reader's college entrance examination?Li Yang can't do it now...

When it comes to high school mathematics, how can readers come up with such crazy ideas.

"Multiple digits multiplied by a single digit can be multiplied by crosses, as can double digits and triple digits!"

"You will be calculating numbers in the future, and this method can get twice the result with half the effort."

Li Yang intends to finish the lecture, and the commutative law of multiplication is naturally not enough.

Here, Li Yang explained that multiplication only includes integers, and he would not foolishly bring up the concept of multiplying fractions and decimals.

At present, the clansmen can learn slowly, and there is no need to study so carefully for the time being.

"In addition to the commutative law of multiplication, remember, there are two other laws."

On Nine Heavens, in Wa Palace.

Fuxi frowned a little.

Earlier, Li Yang wrote down the 12 by 24 formula and asked another group of people for the result.

Fuxi regarded this question as Li Yang asking him.

While he was silently calculating, the human race who was questioned below drew a few random drawings on the ground and calculated the result earlier than him.

Fuxi didn't think that this human race would be smarter than himself, but in terms of the results of this list, he was indeed a bit slower.

In the end, he finally figured out that according to the definition of multiplication, the answer was exactly the same as that of the human race!

Why is that human race so fast?

There is only one possibility that Fuxi can think of.

That is, the human race uses the cross multiplication method to multiply multiple digits, mastering the cross multiplication method can calculate the result faster!

What exactly is cross multiplication?

Li Yang didn't know that Fuxi in the Nine Heavens was thinking about it. In addition to the law of commutation, multiplication also had the law of associativity and the law of distributiveness.

These two multiplication rules are equally practical.

The latter Li Yang mentioned a little earlier.

Now it is natural to focus on it.

In terms of mathematics, Li Yang has strict requirements on himself and cannot be sloppy.

"Let's talk about the law of distribution first."

"The distributive law, regarding the multiplication of the sum of two numbers and a number, you can first multiply them separately, and then add them..."

"E.g......"

Li Yang took the column formula as an example, and explained to several people what the distributive law is.

Diving deep and going deep, from slow to fast, it doesn't take much time to explain a multiplication distribution law.

The associative law of multiplication is simpler.

"When multiplying three numbers, multiply the first two numbers first or the last two numbers first, and the result will not change!"

"I told you about the multiplication of multiple digits, and naturally there are three times of multiplication..."

Two formulas, or two rules.

Fu Xi heard it clearly, these two rules seem to be not difficult?

"When multiplying three numbers, multiply the first two first or the last two first, the product remains the same?"

"parentheses?"

"Distributive law, the sum of two numbers is multiplied by a number, can these two numbers be multiplied first? Then add?"

Fuxi multiplied single digits to verify that the result Li Yang said was correct.

There is nothing wrong with the rules!

If these two laws are correct, wouldn't the cross multiplication method be more important?

It's just how to make Li Yang say it again?

……

After the associative law of multiplication and the law of distributiveness, Li Yang's teaching today ends here.

What I'm talking about today involves '()' and mixed operations.

After finishing the division on the second day, Li Yang was ready to talk about mixed operations.

Take it step by step, don't jump too big!

And those symbols...

Li Yang was quite hesitant, how should I explain those symbols?

Symbols exist not only in mathematics, but also in writing.

',. ! ? ...' and other symbols.

I finally understand why the teaching in my previous life was so detailed.

There are too many subtleties, and a little carelessness will cause knowledge loss!

Li Yang is not only what will be lost in his teaching.

If it is said that knowledge has not been lost, he himself does not believe it.

Do you really think he is a physical education teacher who understands the king?

The charcoal cellar is still steaming, and the finished charcoal can be dug out after a few days.

As for whether it will be successful, Li Yang has no idea in his heart.

In short, he strictly followed the steps of burning paper and charcoal pits.

Should not fail.

The charcoal cellar does not need to be moved, and Li Yang is not worried that someone will move it.

Around the charcoal cellar are clansmen.

They didn't wait for the elder brother's order, so they spontaneously found someone to surround the charcoal cellar!

The people of the clan respect Li Yang, and they will spontaneously protect what he does.

They don't know the truth, they only know that the big brother made things for the whole human race.

If the people of the clan can do this, Li Yang's protection is not in vain!

"Big brother!"

After studying, Xia An came running.

There are two people beside him.

"Big brother!"

In front of Li Yang, the two bowed their heads respectfully.

"These are the two assistants I have chosen!"

After Xia An learned from Li Yangna what assistants were, she called the two younger brothers as assistants.

"Brother, I called them here because I want you to give them names!"

Li Yang smiled wryly, Xia An called two assistants, he thought that Xia An would finish counting the number of houses so quickly.

Who knew it was just a name.

The two younger brothers were brought by Xia An, and Li Yang would not refuse to give them names.

The two younger brothers are also young, and their faces are about seventeen or eighteen years old in their previous lives.

Speaking of this, except for the face-faced people like Zhu Meng, the rest of the people in the human race are quite handsome.

Even the second child, who is so tall and tall, has an immature face.

The age of the tribe is not very old.

The faces are all between seventeen and eighteen years old.

Here also refers only to the face.

After all, based on the birth date of the human race, they were less than ten days old, and they were born as giant babies.

The two younger brothers are about two meters tall, one with dark skin and the other with fair skin.

Compared with the latter, the former is a bit more majestic.

"There is."

Li Yang looked at the dark-skinned younger brother.

He whispered: "Your name is Xia Yong."

"And you... Xia Ning is fine!"

The human race can be safe, and the Huaxia Yongning.

The wish in Li Yang's heart.

The motherland of the previous life is no longer visible, only the wishes in my heart.

"Thank you bro!"

Xia Yong and Xia Ning had excited faces. They also have names from today.

"Xia An values ​​you two so much, don't let him down!"

Li Yang comforted the two of them, and put his gaze on Xia An.

"Before the sun sets today, give me the housing statistics!"

The house is fixed, and the human race feels at ease.

Now the tribe has no concept of "home".

In the previous life, even if Li Yang was exhausted from working outside, as long as he climbed back to the nest, his whole body would feel as if he had been comforted, and he would be given enough strength to work for the next day.

Day after day, year after year, I can finally crawl back to the nest after being tired.

If the clansmen have a house, if they have a heart, they will gradually have a 'home'!

Before sunset, Li Yang got the housing figures from Xia An's statistics.

With specific data, Li Yang will have a better idea in his mind if he mobilizes the personnel arrangements of his tribe!