Reward score: 0-9 days and 22 hours before the end of the question.
1. There is a cube with all red faces, and it takes at least several cuts to get 75 cubes with non-red faces.
a . 1 1 b . 18 c . 16d . 17
There are many square floor tiles. If you put them together to make a big rectangle with an aspect ratio of 5:4, there are 38 left. If you change it to a big rectangle with increased length and width, it will be 53 pieces less. How many square bricks are there in this batch?
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1. There is a cube with all red faces, and it takes at least several cuts to get 75 cubes with non-red faces.
There are many square floor tiles. If you put them together to make a big rectangle with an aspect ratio of 5:4, there are 38 left. If you change it to a big rectangle with increased length and width, you will lose 53 pieces. How many bricks are there?
Xiao Wang rides a motorcycle to and from A and B with an average speed of 48 kilometers per hour. If he walked 42 kilometers per hour when he went, what was the average speed when he came back?
Mickey Mouse and Donald Duck run a 5000-meter race. The speed of Mickey Mouse is 125m, and that of Donald Duck is 100m. But Donald Duck has an electronic remote control, which can force Mickey Mouse to back off. Without giving a command at a time, Mickey Mouse will multiply the original speed by 10% and step back for one minute, then at the original speed.
My brother needs 16 minutes to get home from school, and my sister needs 24 minutes. My brother left home two minutes after my sister left school. When we met, my brother walked more than my sister 120 meters. How far is it from school to home?
200 granite blocks have been mined, of which 120 blocks weigh 7 tons each, and the rest weigh 9 tons each, and each train can carry up to 40 tons. How many cars do you need to transport these stones?
The two model planes are bound by metal wires with different lengths and rotate horizontally around the same fixed point in opposite directions. It takes 30 seconds to turn a plane inside and 60 seconds to build a canal outside. If you build 8 meters more every day, you can finish it 4 days ahead of schedule. If 8 meters are built less every day, it will be delayed for 8 days. How long is this canal? How many seconds did it take from the first time I missed each other to the second time I was wrong?
There are some apples in the box. A child takes them out of the box. The rule of taking them is: take out half of the total number of apples in the box at a time, and then put one back. In this way, after the children made it in 2006, there are still two apples in the box. At first, there were () apples in the box.
Xiaoling bought 100 package of rapeseed, tomato seeds and carrot seeds *** 100, one package of rapeseed 3 yuan, one package of tomato seeds 4 yuan and seven packages of radish seeds 1 yuan. How many bags did she buy?
"There are 100 coins, all of which are replaced by equivalent nickels, and the total number of coins becomes 79. Then, 1 coin was replaced by equivalent nickel coins, and the number of coins became 63. How much are the original 2 cents and 5 cents worth? "
1. One day after the heavy snow, Party A and Party B measure the perimeter of a flower bed from the same point and in the same direction, with Party A measuring 54 cm each step and Party B measuring 72 cm each step. Because the footprints of two people overlap, only 60 footprints were left in the snow. Q: What is the circumference of this painting?
2. The labor remuneration paid by the owner to employees is: silver coins worth 72p for working more than 12 hours per day, and copper coins worth 27p for working more than 8 hours but less than 12 hours. A few days later, the workers got silver coins and copper coins of the same value. Q: How many hours did the workers work for the master at least at this time?
There are less than 65,438+0,000 athletes attending the opening ceremony of the school sports meeting, and the athletes are divided into four teams. After admission, if teams are arranged in the column of 65,438+02 or 65,438+04, the last row is afraid of 8 people, and if they are arranged in the column of 8, it is just right. Q: How many athletes attended the opening ceremony?
& lt 1 & gt； Odd numbers are arranged in 2, 3, 2 and 3 respectively: (1, 3), (5, 7, 9), (1 1, 13), (15,/kloc-0.
* 1*. If the sum of the first few items in the column number initially exceeds 1000, which group is this odd number?
*2*. What is the sum of the figures in the twentieth group?
& lt2> has a series of numbers: 2, 5, 4, 5, ... Starting from the third number, each number is equal to the remainder of the sum of twice the previous number. What is the sum of the previous 100 numbers?
& lt3> From the natural number (1, 2, 3, ..., 2008) in 2008, you can take at most (), so the sum of any two numbers is an integer multiple of 88.
& lt4> Write down the natural number 1, 2, 3, ... and then form a number123 456 78910/21315438. ...
Two people, Party A and Party B, go to the railway station after work. They started along the same route. Party A rides a bicycle for 20 kilometers per hour, and Party B rides a bus for 30 kilometers per hour. As a result, Party A arrived at the railway station 1 hour later than Party B. How many kilometers was it from work to the railway station?
A cylindrical bucket with a bottom radius of 20 cm is filled with water. Now, a conical iron block with a bottom area of 3 14 cm sinks into the water, and the water level rises by 8 cm. What is the height of this tapered iron block?
On the circular runway with a circumference of 400 meters, there are two AB points with a distance of 100 meters. Both parties run back to each other from AB at the same time. After they met, Party B turned and ran in the same direction as Party A. When Party A arrived at A, Party B just arrived at B. If the running speed and direction of Party A and Party B remained the same in the future, how many meters did Party A run from the beginning when it caught up with Party B?
Zhang Ling walks to school along the highway at a speed of 4 kilometers per hour. Along the way, she found that a bus passed behind her every nine minutes, and every seven minutes she met an oncoming bus. If the bus interval is the same and the bus speed is the same, how many minutes is the bus interval?
A car goes from A to B. If the speed is increased by 20%, it can arrive one hour earlier than the original time; If you drive at the original speed of 120km and speed up by 25%, you can arrive 40 minutes earlier. How many kilometers is it between A and B?
Two factories, A and B, produce jackets and trousers of the same specifications. A factory produces jackets every month 18 days, pants every month 12 days, and produces 600 sets every month. Factory B needs 15 days to produce tops and 15 days to produce pants, with 600 sets per month. Q: Now, after the merger of the two factories, how many sets can be produced at most every month?
A, B and C are all reading the same story book. There are 100 stories in the book. Everyone starts with a story and reads it in sequence. It is known that A has read 75 articles, B has read 60 articles and C has read 52 articles. So, how many stories have A, B and C read together?
3. Ten people each carry a bucket and receive water at the faucet at the same time. The first person's bucket needs 1 minute to fill with water, the second person's bucket needs 2 minutes to fill with water, and so on. If there is only one faucet, properly arranging the queue order of these ten people can make the total time spent by each person as small as possible. Q: How many minutes will it take?
The earliest lighthouse in the world was built in 270 BC. The tower is divided into three floors, each with a height of 27 meters. The base is a regular quadrangular prism, the middle is a regular octagonal prism and the upper part is a regular cone. What is the volume of the upper half?
1+2+3.....+ 1999999+2000000=? To simplify, five digital cards: 0, 2, 4, 6 and 8 can form different three digits.
There are about 20 strawberries on a plate, and several children share them. If everyone is divided into three parts, the remaining two; If everyone is divided into four parts, that's three parts. This plate of strawberries can be bought.
Fill in the three boxes of the six-digit number 3□ 2□ 1□ respectively, so that the number can be divisible by 15. The smallest of these six numbers is.
March 19, 2005 is Saturday, so this year's teacher's day is.
A book has 200 pages, and the number 1 appears once in all page numbers.
A train goes from city A to city B. If you drive at a speed of 24 kilometers per hour, you will arrive at City B in the afternoon 1; If you drive at a speed of 40 kilometers per hour, you will arrive at B city in the morning 1 1. At what speed should this train travel so that it can reach B city at noon 12?
1.4*5+5*6+6*7+...25*26+26*27=?
2. How many odd numbers are there in the product of11(1in 2006) * 99 ... 99 people (9 people in 2006)?
3。 From any n different integers, you can definitely find that the difference between two numbers is a multiple of 8, so what is the minimum value of n?
If the sum of a four-digit number and a three-digit number is 1999, and the four-digit number and the three-digit number are composed of seven different numbers. So, how many such four digits can there be at most?
This is the fourth question in the final examination paper of the 15th "Spring Cup" primary school students' mathematics competition in Beijing, and it is also the question that the contestants lose the most points.
Get a = 1, b+e = 9, (e≠0), c+f = 9, d+g = 9.
In order to calculate the maximum number of such four digits, conditions A, B, C, D, E, F and G are different from each other. It can be seen that there are seven ways to choose B (B ≠ 1, 8,9) and six ways to choose C (C ≠ 1, 8,9). So according to the principle of multiplication, there can be at most four digits like (7×6×4=) 168.
After answering the question 1, if we think further, it is not difficult to think of the following question.
Question 2: There are four cards with the number 1 written on both sides. The first one is 0 and 1, and the other three are 2 and 3, 4 and 5, 7 and 8 respectively. Now take out three cards at random and arrange them in a row. How many different three digits can a * * * make up?
This question is the preliminary examination question of the 14th "Spring Cup" mathematics competition for primary school students in Beijing. The solution is:
After that, 10 digit b can take the six digits of the other three cards; The last number c can be the four numbers of the remaining two cards. To sum up, a * * * can form different three digits * * (7× 6× 4 =) 168.
Is it a coincidence that the scores of two counting questions in the "Spring Cup" competition for two consecutive years are 168?
Careful readers can easily find that as long as we deal with the question 1 a little, it can become the equivalent form of question 2. In other words, 1 and 2 are essentially just two different formulations of the same question.
The equivalent form of the question 1 is as follows:
Now four cards are constructed, with numbers written on the front and back. The first one says 0 and 9,
The good thing is that three cards are randomly selected from these four cards and arranged in a line, so how many different three-digit numbers can be formed.