Math diary spent 300-400 words in the sixth grade last semester, and the big brother will help him tomorrow.

Before numbers appeared, people had a way to tie knots to record things. For example, you have five sheep and tie five knots. Later, it was found that if 100 was tied one by one, it would not only be troublesome to tie the knot, but also ugly. Therefore, people have learned to use different colors or different shapes of knots to represent different units of numbers.

Later, people found it troublesome to count knots, so they began to count them with some items, such as the moon representing "1" and so on. At this time, someone counted with fingers, toes and pebbles.

People find this method inconvenient, so they learn to use symbols to represent numbers, such as "|" in ancient Egypt for "1", "n" for 10, wings for 10000, birds for 65438+ million and so on. And China at this time with wood, bamboo, bones and so on to count, called "calculation". Although this kind of counting will be simpler than before, it is helpless in the face of huge numbers. If you remember "1.500 million", how many bones to pile and how many birds to draw!

As a result, the ancient Indians invented several numbers, the most popular of which belongs to Brahmanism, the embryonic form of Arabic numerals now, but it is still not as simple as it is now. For example, "0" is "●" in ancient Indian numerals. In this way, a set of basic figures is produced. Later, this number spread to Arabia, and the Arabs revised this number into the current Arabic number. Arabs spread this number to Europe, and European businessmen thought it was invented by Arabs, so they called it Arabic numerals. At the same time, other countries also produced some figures, such as Roman numerals, which were also developed at this time.

Then, people invented binary, ternary and so on. However, because the decimal system should be the most widely used in real life, it is used more now. This counting method has been used up to now and is the simplest counting method at present.

Whenever I walk into the campus, a very eye-catching sign will appear in front of me, which reads a sentence, that is, "learn mathematics in life and use mathematics in life." Yes! We can't live without mathematics. If we don't study math, we will make a lot of jokes.

Take an incident that happened to me two years ago. That day, I got up early, and my mother asked me to help her go downstairs and buy some breakfast. Then I went downstairs with five dollars. Go downstairs, buy breakfast, pay the money. The boss said, "These come to * * * two dollars and fifty cents. I'll give you two dollars and fifty cents. " Then he gave me the money. As soon as I saw it, I quickly said, "No, no! If you give me less than one yuan, you should give me three yuan and fifty cents! " After hearing this, the boss was stupid, hesitated for a while and said to me, "Little friend, you have miscalculated, that is, the 2.50 yuan you are looking for!" " "As soon as I heard this, I was in a hurry to defend myself:" Uncle, you have miscalculated, obviously it is three yuan and fifty cents! "The proprietress on the side saw it and shouted at me in an angry dialect:" Look at this child, he is not young, how can he not even know the most basic arithmetic! " Everyone who ate there laughed "ha ha ha". I looked at it and ran home sadly, telling my parents all the ins and outs of the matter. Mom and dad listened, and they also laughed and leaned forward and backward. I said angrily, "Even you laugh at me!" Dad quickly explained, "It's not that we love to laugh at you, but that you didn't understand and think about Jiao Yuan's score in mathematics. Then I'll ask you what $2.50 is. "

"A dollar."

"How much are those two twenties?"

"Four dollars, of course!"

Finally, I finally understood that my father's explanation was not serious. Since then, I have never made the same mistake again.

I will never forget this joke. It taught me a lesson, which will be imprinted on my mind forever.

Students, you must study math seriously. Mathematics is not that simple. After learning, you must remember: learn mathematics in your life and use it in your life.

After school in the afternoon, the class teacher gave us a homework assignment, asking everyone to find a way to measure the volume of disposable chopsticks and record the measurement process in the form of math diary. On the surface, this assignment is a mathematical practice, but in fact it may have a deeper meaning, because the use of disposable chopsticks is related to environmental protection.

As soon as I got home, I sat quietly at my desk and thought about it. Disposable chopsticks are irregular three-dimensional figures. How do we measure its volume? I scratched my head and shook my head while reasoning. ...

Finally, small eyes. I can put disposable chopsticks in a container full of water, so that the water in the container will overflow. Isn't the amount of splashing water as big as chopsticks? But chopsticks are lighter than water and will float on the water. What shall we do? Can you fix chopsticks with stones or tape or something? I think it should be possible, but these methods are too troublesome to measure. If only there were a simpler way! After thinking hard, I finally smiled proudly.