Tisch
In our concept, "1" is the smallest number, the first number of an integer, and the first number of ten thousand. Yes, "1" is the first number of ten thousand, and its position is also the most special. Let's meet this magic number with me.
First, the smallest number.
The ancient and huge family of natural numbers consists of all natural numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. The smallest one is "1", which cannot be found. You can look for it if you are interested.
Second, there are no natural numbers.
Maybe you think you can find a natural number (n), but you will immediately find another natural number (n+ 1), which is greater than n, which means that you will never find a natural number in the family of natural numbers.
Third, "1" is indeed the smallest in the family of natural numbers.
The natural number is infinite, and "1" is the smallest of the natural numbers. Some people disagree that "1" is the smallest natural number, saying that "0" is smaller than "1" and "0" should be the smallest natural number. This is wrong, because natural numbers refer to positive integers, and "0" is a non-positive and non-negative integer, so "0" does not belong to the family of natural numbers. "1" is indeed the smallest in the family of natural numbers.
Don't underestimate the smallest "1", which is the unit of natural numbers and the first generation of natural numbers. Humans first recognized "1", and only by using "1" can we get 1, 2,3,4. ...
I told you the special status of "1", which is the first in a thousand miles. Don't underestimate it.
extreme
When it comes to the role of mathematics, we can't finish talking all day and all night. Without math, our life is very inconvenient. So, do you know what mathematics can do in daily life besides simple operations? Can you solve a case like a policeman? Yes, if you don't believe me, look at how Robin Hood solved the case with mathematics.
There is an ancient castle left over from the Middle Ages on the outskirts of Paris, almost as old as Notre Dame de Paris, so it has become a tourist attraction and attracted tourists from all over the world. The following story comes from a tour guide.
There is a dusty bell tower on the top floor of the castle, where a strange man lives. The access to the outside is a wooden staircase, creaking and steep, with dozens of steps, but definitely less than 100.
One night, Alexei, Barton, Kling and Dupont, four strange strangers, visited at almost the same time. They found that the weirdo had been killed and the room looked terrible. The four * surprised, scrambling to escape. Running down the messy narrow stairs (only one person can pass at a time), Alexei went down two steps, Barton went down three steps, Kling went down four steps, and DuPont was able to go down five steps.
After the accident, Grand Theft Auto Arthur Robin disguised himself as a decent gentleman in the upper class and volunteered to solve the case. He found that there were only two steps with four footprints printed on them at the same time.
In order to trace the murderer, it is difficult to do it if the footprints are chaotic, so Arsène Lupin pays special attention to the steps with only one person's footprints. Later results fully proved that his point of view was correct, and finally the murderer was caught and brought to justice.
What I want to ask you now is, how many steps on the wooden stairs leading to the bell tower are only printed with one person's footprints (no matter who)?
Answer:
Because the multiple of 4 must be a multiple of 2, Kling's situation can be ignored, thus saving one person. The least common multiple of 2, 3, 4 and 5 is 60, and 60 is less than 100, so the wooden stairs of the bell tower have 60 steps.
Alexei's footprints fall on the 2nd, 4th, 6th, 8th, l0, 12, …, 58th and 60th steps, but the steps of 2×3 and its multiples should be excluded. Similarly, it is necessary to exclude ladders at all levels with a multiple of 4 and ladders at all levels with a multiple of 5. So there are 2 14, 22, 26, 34, 38, 46, 58 * * levels left. Its general form is 2×p (where p= 1 and prime numbers other than 2, 3 and 5).
Barton's footprints fall on the 3rd, 6th, 9th, 12, …, 60th steps, but the 6th, 12, 15, 18, … steps are mixed with others' footprints and should be excluded, leaving the 3rd, 9th and 60th steps.
I have said that Kling's situation can be ignored. Finally, let's look at DuPont's situation. Obviously, the steps that only left his footprints were level 5, 25, 35, 55 and * * * 4.
So the answer to the question is 8+8+4=20.
Tisso
"How many times does the hour hand turn a day?" Teacher Lin asked us.
Our answers are varied, some say 50, some say 100, just like solve riddles on the lanterns. A dozen students were punished for standing illegally. I have the final say, and I know it well, but I am also afraid that I will be punished if I do something wrong. Ask me a question, I told her, but it happened that teacher Lin called me at this moment: "Tang Ruiqi, you say." I stood up and blurted out without thinking, "24 laps."
Teacher Lin said, "Yes, please sit down!"
But some students said, "Teacher Lin is wrong, not 24 laps."
Teacher Lin said, "Think about it. It takes an hour to walk an hour. Isn't 24 hours a day 24 times? " Teacher Lin drew a picture while talking, and the students understood it as soon as they talked.
In fact, these things are very close to our lives. Just think about it.