That is, everyone eats 1\5. Then 1 ÷ 5 = 1 in 5 can be obtained.
And the first one.
, in Chenghua.
For example: 265438+56 takes 0 = 8 takes 3 = 8 ÷ 3 = 2 and 2 takes 3.
Compare the scores by division.
It's sunny today, so I watch it at home.
The Olympiad suddenly found such a problem: compare1111,1 165438+. Suddenly, I became interested and took a pen and "brushed" it on the toilet paper. Soon, I found a solution That is to put these two
Chenghua
Then, using the law of fractions, the smaller the denominator, the greater the fraction. Solve111111
My mother listened to my words, looked at the topic and laughed loudly: "hey, I thought there were many problems." Isn't it a simple score comparison? " After listening to my mother's words, I immediately got angry and said, "What, this question is difficult." After that, I satirized my mother: "How tall you are, this topic is not a piece of cake for you!" " "Mom smiled:" OK, OK, I won't argue with you, but if you can solve this problem from two aspects, it will be a high level. "I listened to my mother and looked at the problem again. I couldn't help wondering," There are other solutions. " I was surprised and said, "Of course," and my mother said I wouldn't do it anyway. It seems that your level is still low. "I buckled my mother's words, and I was so angry that I did it again, proving that I am a high-level person. Finally, through my efforts, the second method came out, which is to compare their sizes by division. You see, if one number is less than another number, then the quotient of this number divided by another number must be
Similarly, if one number is greater than another, the quotient of this number divided by another number must be greater than 1. Using this rule, I use1111÷11. Needless to say, it must be the closest two, so1111111//. 1 1 1× 1 1 1/ 1 1 1 1 1、 1 1 1 1 1 / Kloc-0/11111×11,so it is. 1 1 1 1 1/ 1 1 1 1。
Today, I saw such a problem in the training of Mathematics 1+2, which was on a building area of 648 square centimeters.
In the casting, the largest one is removed and two opposite sides are used as the bottom.
, the rest.
What is the area?
Seeing this topic, I was very confused and thought: just say a bottom area, how to do it? My mother sitting in the chair looked at it, smiled at me and said, "Hum, she can't even do this problem."
I know mom uses it
The purpose is to irritate my competitiveness and let me finish this problem. In order to make mom think that her
When I succeed, I just bite the bullet and do it, but I can't figure it out. But I'm not discouraged. I persisted and finally succeeded.
According to the figure (figure), we can find that a hole as big as the original cylinder will come out after cutting off a cylinder, although the hole is the same as the original cylinder.
The volume is the same, but their surface areas are different, but the areas of the two bottom surfaces are smaller than those of the original cylinder.
Therefore, the remaining graphic area should be equal to the area of the six faces of the cube minus the two bottom faces of the cylinder+the side faces of the cylinder.
The formula is 628× 6-628× 3.14 ÷ 4× 2+628× 3.14.
Today is another sunny day. I was wandering in the street when I suddenly saw a lot of people gathered not far away. I ran for a year, and the result was a prize-winning game. "Hum, what's fun about winning the prize?" I was bored when the person next to me quickly said, "It's not fun to grab the prize, but there is a big prize that can attract people." I asked eagerly, "What is it!" "50 yuan money." The man with big eyes said. I'm very excited to hear that. "I have to try anything for such an attractive prize." Then I asked the shopkeeper how to grasp the rules. The shopkeeper said, "This is 24 Mahjong, and it says 12 5, 12 10. You can only catch 12 mahjong at a time. If the total number of 12 mahjong targets is 60, then you can win the 50 yuan Prize. " Without rolling up my sleeves, I took out 5 yuan money from my pocket and gave it to the shopkeeper.
Although I won 10 times, I still didn't win the grand prize.
When I got home, I thought about it and felt something was wrong. I think, to get 60 points, all 12 mahjong should be marked with 5. In the best case, the first 1 second catch 1 5, the second catch of two 5 s and the third catch of three 5 s will cost at least 6 yuan money. But what if the target number of mahjong is 10 or the sum of the two is the same, how many times will it cost?
Finally, after some consideration, I finally figured it out. I rushed to the street to get even with it, but it had disappeared without a trace.
There are two candles with different thicknesses. A thin candle is twice as long as a thick candle. It takes 1 hour to light a thin candle and 2 hours to light a thick candle. Once there was a power failure, two used candles were lit at the same time. When the phone call came in, I found that the remaining length of the two candles was the same. How long was the power outage?
Solution: If the candle length is 1 and the burning speed is (1)1÷ 2 =1/2 (2) 2 ÷1= 2, the formula is: 65438.
Solution: Set the power outage time as x hours.
1— 1/2X=2—2X
X=2/3
A: The power outage time is 2/3 hours.
I saw such a problem in the "two-color class for primary school students" this afternoon.
The bottom radius of the cone is 8 decimeters, and the ratio of height to bottom radius is 3: 2. What is the volume of this cone?
Analysis: This is proportional distribution.
Plus the cone problem.
. To calculate the volume of a cone, you need to know the bottom area and height of the cone. The topic is about the radius of the bottom surface, so we can find the bottom area, but we don't know the height. You can find it according to a condition, and convert the ratio into a number that accounts for a fraction of the known number, so that you can know that the height accounts for 3/2 of the radius of the bottom surface. After calculating the height, calculate the volume of the cone according to "V=SH÷3".
whenever
There will be a sea of people on the giant mountain, so some swindlers have come up with some deceptive tricks, such as gambling on something on a plate.
Prop is very simple, draw a big circle on a board, and fix a rotatable pointer in the center of the big circle with a nail. The great circle is divided into 24 equal squares, and the needles in the squares can rotate. The box says 1-24 equal numbers, which are worthless in the odd box, but almost all even numbers are valuable.
The gameplay is also very simple. Set the pointer to 1 first, then you dial the pointer again, and the pointer will start to rotate and finally stop in a grid. Then press the number marked on the grid where the pointer is located and dial the pointer again. N- 1 grid, where n is the number marked on the grid.
This is just a little math game. In fact, no matter which box you dial, you can only lose money, not make money. Because when the pointer turns to an odd cell, the number of cells dialed is odd-1= even, and odd+even is only equal to odd, so it is impossible to turn to an even cell and nothing valuable can be obtained. If the pointer turns to an even grid and the number of grids dialed is even-1= odd, and odd+even = odd, then you won't get anything of value.
Today, I listened to "Multimedia Teaching".
and
"one hall"
After listening to it, he had a feeling that multimedia was originally used for teaching assistance.
Teachers' organizational means can better serve teaching and increase the novelty, uniqueness, deepening and attraction of teaching. For such a long time, quality-oriented teaching has been proposed for students, but after listening to several multimedia teaching classes, the shadow of injection has been revealed, which has taken root before injection teaching, but it must be changed slowly in normal teaching. On the other hand use
It can arouse students' enthusiasm, and the teaching is centered on student service, not computer service. Whether it can lead to the * * * of the majority of front-line teachers!
Today is a sunny noon. Reading a math newspaper at home, I came across the topic of seeking comparison and simplification. I don't think I learned this last semester. But on second thought, I'd better have a look!
There are differences and connections between "seeking comparison" and "simplifying comparison". Students should pay attention to the following points when studying:
1, the purpose of comparison is to find the result of dividing the previous item by the later item; The purpose of simplifying a ratio is to make a ratio equal to the former and the latter.
Integer ratio of.
2. Calculating the ratio is similar to simplifying the ratio. There are the following:
Basic properties of (1) utilization rate. For example:
5/6:1/2 = (5/6× 6): (1/2× 6) ① The ratio is 5/3; ② The simplified ratio is 5∶3.
(2) The relationship between ratio and division. For example:
6.3∶0.9=6.3÷0.9① The ratio is 7; ② The simplification ratio is 7∶ 1.
(3) Use the relationship between proportion and score. For example:
16: 20 =16/20 = 4/5 ① the ratio is 4/5 or 0.8; ② The simplified ratio is 4∶5.
3. The result of the ratio is a number, which can be an integer, a decimal or a fraction; The result of simplifying ratio is a ratio, which can be written as
or
The form of (see the example above) cannot be written as integer, decimal or
Yes, the result of the simplified ratio should be read as several ratios, such as:16: 20. The simplified ratio is 4/5, which should be read as: 4: 5.