1. In life, we often use the numbers , 1, 2, 3, 4, 5, 6, 7, 8 and 9.

so do you know who invented these numbers? These digital symbols were originally invented by ancient Indians, then spread to * * *, and then spread to Europe from * * *. Europeans mistakenly thought that they were invented by * * * people, so they were called "* * * numbers". Because they have been circulated for many years, people still call them * * * numbers. Now, the number * * * has become a universal digital symbol all over the world.

2. Jiujiuge is the multiplication formula we use now. As far back as the Spring and Autumn Period and the Warring States Period BC, Jiujiu songs have been widely used by people.

In many works at that time, there were records about Jiujiu songs. The original 99 songs started from "99 81" to "22 get 4", with 36 sentences.

Because it started from "9981", it was named 99song. It was between the 5th and 1th centuries that the Jiujiu Song was expanded to "one by one".

It was in the 13th and 14th centuries that the order of Jiujiu songs became the same as it is now, from "one to one" to "9981". At present, there are two kinds of multiplication formulas used in China. One is a 45-sentence formula, which is usually called "Xiao Jiujiu"; There is also an 81-sentence sentence, which is usually called "Da Jiu Jiu".

3. Circle is a seemingly simple but actually wonderful circle. Ancient people first got the concept of circle from the sun and the moon on the fifteenth day of the lunar calendar.

Even now, the sun and the moon are used to describe some round things, such as the moon gate, the yueqin, the moon shell, the sun coral and so on. Who made the first circle? The stone balls made by the ancients more than 1 thousand years ago are quite round.

As mentioned earlier, cavemen 18, years ago used to drill holes in animal teeth, gravel and stone beads, and some of those holes were round. The caveman drilled the hole with a pointed device, one side could not be penetrated, and then drilled from the other side.

The tip of the stone tool is the center of the circle, and half of its width is the radius. You can drill a round hole by turning around. Later, in the pottery age, many pottery were round.

Round pottery is made by putting clay on a turntable. When people began to spin yarn, they made round stone or ceramic spinning cocoons.

Banpo people (in Xi 'an) built round houses 6 years ago, with an area of more than 1 square meters. The ancients also found that it was more economical to roll round wood.

Later, when they were carrying heavy objects, they rolled some logs under big trees and big stones, which of course saved much effort than carrying them. Of course, because the log is not fixed under the weight, you have to roll the log rolled out from the back to the front and pad it under the front part of the weight.

About 6, years ago, Mesopotamia made the world's first wheel-a round wooden plate. About 4 years ago, people fixed round wooden plates under wooden frames, which became the original cars.

because the center of the wheel is fixed on a shaft, and the center of the wheel is always equal to the circumference, so as long as the road is flat, the car can move forward in a balanced way. You can make a circle, but you don't necessarily know the nature of a circle.

The ancient Egyptians believed that the circle was a sacred figure given by God. It was not until more than two thousand years ago that Mozi in China (about 468- 376 BC) gave a definition to the circle: "One China has the same length".

It means that a circle has a center, and the length from the center to the circumference is equal. This definition is 1 years earlier than that defined by the Greek mathematician Euclid (about 33 BC-275 BC).

pi, that is, the ratio of circumference to diameter, is a very strange number. "Zhou Bi suan Jing" says that "the diameter is three times a week", and pi is regarded as 3, which is only an approximation.

When the Mesopotamians made the first wheel, they only knew that pi was 3. Liu Hui in Wei and Jin Dynasties annotated Nine Chapters of Arithmetic in 263 AD.

He found that "diameter is three times a week" is only the ratio of the circumference and diameter of a regular hexagon inscribed in a circle. He founded the secant technique, thinking that when the number of edges inscribed in a circle is infinitely increased, the circumference is closer to the circumference of a circle.

He calculated the pi of the 372-sided polygon inscribed in the circle, π= 3927/125. Would you please convert it into a decimal, and see how much it is? Liu Hui has applied the concept of limit to solving practical mathematical problems, which is also a great achievement in the history of mathematics in the world. Zu Chongzhi (AD 429-5) continued to calculate on the basis of predecessors' calculations, and found that pi was the earliest accurate value of seven decimal places in the world between 3.1415926 and 3.1415927. He also used two fractional values to express pi: 22/7 is called the approximate ratio, and 355/113 is called the density ratio.

Would you please convert these two fractions into decimals, and see how many decimal digits are the same as the known pi today? In Europe, it was not until the 16th century, 1 years later, that Germans Otto (AD 1573) and Antuoni Z got this value. Now that there is an electronic computer, pi has been calculated to more than 1 million after the decimal point.

4. In addition to counting numbers, mathematics needs a set of mathematical symbols to express the relationship between numbers and numbers, numbers and shapes. The invention and use of mathematical symbols are later than numbers, but they are much more numerous.

There are more than 2 kinds commonly used now, and there are more than 2 kinds in junior high school math books. They all had an interesting experience.

For example, there used to be several kinds of plus signs, but now the "+"sign is commonly used. The "+"is derived from the Latin "et" (meaning "and").

in the 16th century, Italian scientist Nicolo Tartaglia used the first letter of Italian "più" (meaning "add") to mean add, and the grass was "μ", which finally became "+". The number "-"evolved from Latin "minus" (meaning "minus"), abbreviated as m, and then omitted the letters, it became "-".

It is also said that wine merchants use "-"to indicate how much wine is sold in a barrel. In the future, when new wine is poured into the vat, a vertical line is added to the "-",which means that the original line is erased, thus becoming a "+"sign.

in the 15th century, the German mathematician Wei Demei officially determined that "+"was used as a plus sign and "-"was used as a minus sign. Multipliers have been used for more than a dozen times, and now they are commonly used in two ways.

One is "*", which was first put forward by the British mathematician Authaute in 1631; One is "",which was first created by the British mathematician Herriot. German mathematician Leibniz thinks: "*".

Math tips for grade 2.5

A math joke 1. Once, my mother patiently inspired Ya Ya to do arithmetic problems: "Ya Ya, you have learned to do subtraction, haven't you?" Come, let's see, how much is 4 MINUS 2? " "It's 2, Mom."

"that's right, good boy. So, what about 5 MINUS 5? " "Five minus five, minus five.

. "Ya Ya muttered," I won't, Mom. "

"Son, you can't help it! Think about it, for example, you have five coins in your pocket, but suddenly, all five coins fall out. Tell me, what else is in your pocket? " Yaya flashed her big eyes and said, "Did you drop it? Well, there is still a hole in my pocket! " 2. "I always get 1 in arithmetic."

"That's because you learned well." "But I never listen in class."

"That's because you are smart and know how to work hard when you come home from school." "Smart? A little, but after school, I am a person who deals with football. "

"Then you must have cheated in the exam." "I can't say that. I didn't copy books or peek at others. How can I be considered cheating?"

"What's the matter with you?" "I kicked Jim, the bookworm in front, in his chair." "If you don't, you won't. How can you be so naughty?"

"I kicked the first foot, and he stretched out five fingers backwards with his hand." "What does this mean?" "The answer to the first question 2+3."

"oh ... what if I ask the answer to question 1, 5*8?" "It was after I kicked the tenth foot that he stretched out four fingers first and then clenched his fist immediately, so I knew the answer of 4." 3. The teacher published the results: "Xiaohua scored 3 points, Xiaoming scored 2 points ..." Pig: I got points! Dog: What should I do? Me too ... Pig: We both got the same score in the exam. Will the teacher think we cheated? Legend has it that one day, Zhuge Liang called the soldiers together and said, "Whichever one of you chooses an integer from 1 to 124, keep it in mind. I ask ten questions and only ask for a' yes' or' no'.

after I have answered all ten questions, I will' calculate' the number you have in mind. " Just after Zhuge Liang finished, a counselor stood up and said that he had chosen a number.

Zhuge Liang asked, "Did you choose more than 512?" The counselor replied, "No." Zhuge Liang asked the counselor nine questions one after another, and all the counselors answered them one by one.

Zhuge Liang finally said, "The number you remember is 1." The counselor was very surprised, because this number was really his choice.

do you know how Zhuge Liang calculated it? In fact, the method is very simple, that is, take half of 124 and take it to the tenth time, which is "1". According to this truth, you can find the required number by asking ten questions in a row.

3. Famous mathematical sayings 1. The percentage of Wang Juzhen Chinese scientist Wang Juzhen has a proverb about experimental failure, which is called "There is still a 5% hope of success if you go on, and failure if you don't do it is 1%." 2. Tolstoy's Score When talking about people's evaluation, Tolstoy compared people to a score.

He said, "A person is like a score, his practical ability is like a numerator, and his evaluation of himself is like a denominator. The larger the denominator, the smaller the value of the score. "

1. The essence of mathematics lies in its freedom. Cantor) 2. In the field of mathematics, the art of asking questions is more important than the art of answering questions. Cantor) 3. No question can touch people's emotions as deeply as infinity, and few other concepts can inspire reason to produce fruitful thoughts as infinity. However, there is no other concept that needs to be clarified as much as infinity. Hilbert) 4. Mathematics is an infinite science. Hermanville 5. Problems are the heart of mathematics. P.R.Halmos 6. As long as a branch of science can ask a lot of questions, it is full of vitality. The lack of problems indicates the termination or decline of independent development. Hilbert 7. Some beautiful theorems in mathematics have such characteristics: they are easy to be summarized from facts, but the proof is extremely deep. Gauss 3. Rybakov's constants and variables Russian historian Rybakov said this in the use of time: "Time is a constant, but for the diligent, it is a' variable'. People who use' minutes' to calculate time spend 59 times more time than those who use' hours'. "

2. Write aphorisms with symbols 4. Hua Luogeng's minus sign. When talking about learning and exploration, Hua Luogeng, a famous mathematician in China, pointed out: "To dare to do subtraction in learning is to subtract the parts that have been solved by predecessors and see what problems remain unsolved, which need us to explore and solve." 5. Edison's great inventor Edison used a plus sign to describe genius. He said, "Genius =1% inspiration +99% sweat."

6. dimitrov's sign dimitrov, a well-known international worker movement activist, said when evaluating the work of a day: "We should use time to think about what we have done in a day, whether it is' plus' or' minus', and if it is' plus', we will make progress; If it is'-',you have to learn a lesson and take measures. " 3. aphorisms written in formulas 7. Einstein's formula When talking about the secret of success, Einstein wrote a formula: A = X+Y+Z.

and explained: A stands for success, X stands for hard work, Y stands for correct method, and Z stands for less empty talk. ""If you use a small circle to represent what you have learned and a big circle to represent what I have learned, then the area of the big circle is a little more, but the blanks outside the two circles are our ignorance.

The bigger the circle, the more ignorant faces it touches. " -Zhi Nuo Cauchy (1789–1857) Men Pass Away, but they deeds Abide. People always die, but their achievements last forever.

Laplace (1749–1827) What we know is not much. What we do not know is infinite. C. Hermite (1822–191) Abel has left mathematicians enough to keep them busy for 5 years. When he commented on Abel, he once said, "What Abel left behind can keep mathematicians busy for 5 years.

"Poursin (Poisson, Simé on 1781-184)" Life is good for only two things, discovering mathematics and teaching.

3. Little knowledge about mathematics

Little knowledge about mathematics--------------. The invention and use of mathematical symbols are later than numbers, but they are much more numerous. Now there are more than 2 kinds in common use, and there are more than 2 kinds in junior high school math books. They all had an interesting experience.

For example, there used to be several kinds of plus signs, but now the "+"sign is commonly used.

the "+"sign is derived from the Latin "et" (meaning "and"). In the 16th century, the Italian scientist Nicolo Tartaglia used the first letter of "più" (meaning "add") in Italian to mean add, and the grass was "μ", which finally became "+".

the "-"sign is derived from the Latin "mi"