I want to find out about the Mathematics Olympiad in primary school

Buy a copy of "Qidong Middle School - Olympiad".

The Olympiad is good and has a detailed explanation.

Is it a book, or a few questions? Can you explain the point.

Hua Luogeng Olympic textbook.

Pretty good.

The Primary School Olympiad draws inferences from one another, which is very good.

You can go to the math teacher in the elementary school, they usually have this information

You can look up Olympiad problems on the Internet, or you can buy a book, but first you have to understand before you can teach your child!

Just draw inferences", there are ones for every grade, simple, and easy to learn. There are example questions and analysis, and there are unit type exercises.

Hua Luogeng's Olympic textbooks are available in bookstores.

It would be better to go to the bookstore and buy a book and find a teacher.

There are many books on Olympiad mathematics, and you should buy textbooks according to the level of students and find teachers with deep Olympiad skills to teach, so that children will progress faster.

What is the Primary School Math Olympiad? If you have books, bookstores will have them.

Buy a copy of "Hua Luogeng Mathematics", a very good Olympiad book.

[Answer].

Method 1: When the ten digits are 1, there are 111,210 for a total of 2;

When the ten digits are 2, there are 123 in total; 222；321；420 of 4;

When ten is 3, there are 135; 234；333；432；531；630 of 6;

When the ten digits are 4, there are 147 in total; 246；345；444；543；642；741；840 of 8;

When the ten digits are 5, there are 159 in total; 258；357；456；555；654；753；852；951 of 9;

When the ten digits are 6, there are 369 in total; 468；567；666；765；864；963；7 in total;

When the ten is 7, there are 579 in total; 678；777；876；975；5 in total;

When the ten digits are 8, there are 789 in total; 888；987 of 3;

When the ten digits are 9, there are 1 of 999;

So, there are a total of 45 good numbers that happen to be the average of the first and last digits

Method 2: (correspondence method) according to the title, if the hundred digits and single digits are determined, the ten digits will be determined, so the number of hundreds and single digits is the number of good numbers, and because the parity of the hundred digits and the single digit numbers are the same, there are 9 ways to choose for the hundreds, and there are 5 choices for the single digits after the hundred digits are selected, so there are 9 5 = 45 good numbers.

Are the three numbers different?

The sum of two numbers gives an even number of ......Total: 4*9+4=40, so a total of 40.

Therefore, the maximum number is 23

2.(Math +83 + 74 + 71 + 64) 5 = Math + 4 Math = 683The head of the body hall = 3 + the chief of the tail forest. First formula.

Tail length = (3 + body length) 2....The second formula.

Bring the first formula into the second formula, get.

Tail length = (3 + 3 + tail length) 2

Tail length = 6 meters.

Length = 3 + tail length = 9 meters.

The full length of this big shark = head length + body length + tail length = 3 + 6 + 9 = 18 meters.

Two times up the mountain, down the mountain, a total of time, Xiangzhen and 188 hours to keep an eye on the brigade = 6 hours and 2 minutes.

1) 20 times.

There are 10 numbers to write 8.

80 81 ……89 There are also 10 numbers to write 8.

There are 88 repetitions in two columns, so the number to be written to 8 in 1-100 is 10+10-1=19.

Except 88 to write numbers"8"2 times, 1 time for each of the rest, so write the number 8 (20) times.

2) 21 days.

According to the meaning of the title, it can be seen that the big and small cattle are cultivated together for 4 days, 5 acres are cultivated, 25 acres are cultivated for 20 days, and 3 acres are cultivated on the 21st day.

, the number 8 is to be written (20) times

2.Calves plough 1 acre a day and have to rest for 3 days, big cows plough 2 acres a day and have to rest for 1 day, and big and small cattle plough 28 acres of land together for (21) days. Because the big cow and the calf combined to plough 5 acres of land in 4 days, 25 acres of plough land in 20 days, and then 3 acres of plough land on the 21st day to complete the task.

Times. It is 10 times that 8 appears in the single digit and 10 times in the 10th digit.

Sky. Four days is a cycle, in four days, the calf is one acre, the big cow is four acres, and the 20 days is 25 acres. The 21st just finished plowing the remaining 3 acres of land.

Hope it helps!

Celebration of the gods: 8, 18, 28... Ten in total.

Ten places: reputation loss 80, bucket 81, 82... Ten in total.

20 in total.

Take all 1 is 1 kind.

Take all 2 is 1 kind.

All 3 is 1 kind.

There are 5 kinds of only 1 and 2.

There are 3 kinds of only 1 and 3.

1*3, 3*3) (1*6, slag or 3*2) (1*9, 3*1) take 2 and 3 There are 2 kinds.

3 * 1, 2 * 4) (3 * 2 (3 * 2, 2 * 3) to take 1, 2, 3 has 7 kinds.

There are 20 species in total.

Do you want a title? I have.

1. A pasture is overgrown with grass, and the grass grows evenly every day. This pasture can feed 10 cows for 20 days and 15 cows for 10 days. Q: How many days can it feed 25 cows?

2. Now I want to drain all the water in a pond, but at the same time there is water flowing into the pond at a uniform rate. If you use 8 pumps, you can drain it in 10 days; I can drain it in 20 days with six pumps. Q: How many of the same pumps do I need to drain the water in 5 days?

3. In a garment processing workshop, Group A can process 8 tops or 9 pairs of pants per day, Group B can process 6 tops or 8 pairs of pants per day, Group C can process 6 tops or 7 pairs of pants per day, and 3 groups can cooperate for 15 days, how many sets of clothes can be produced at most?

4. Container A has 150 grams of brine with a concentration of 4%, and container B has a certain concentration of saline, take out 450 grams of brine from B and mix it into a concentration of brine to find the concentration of B.

5, a pool is equipped with two inlet pipes of A and B, in the same time, the water inlet of B pipe is twice that of A pipe, when filling water into the empty pool, start to inject the water of the pool into the A pipe, and then open the B pipe, and the rest is filled by the B pipe alone, and it took 12 minutes and 15 seconds in total. How many hours has the nail tube been on?

6. A pool of water, A and B two pipes open at the same time, 5 hours full, B C at the same time, 4 hours full, now open B pipe for 6 hours, and need A and C to open 2 hours to be full. How many hours can it be filled up?

7. Two trains depart from A and B at the same time, and it takes 20 hours for the express train to complete the journey, and 30 hours for the slow train to complete the journey. After 15 hours of driving, the two cars met. Known that the fast train stopped for 4 hours and the slow train stopped for several hours?

8. For a project, it takes 10 days for team A to do it alone, and it takes 30 days for team B to do it alone, and now the two teams are cooperating, during which team A rests for 2 days and team B rests for 8 days (not resting on the same day). How many days did the project take?

9. How many days does it take for a small raft to drift from city A to city B for 3 days and nights for a ship to travel at the same speed, and 4 days and nights for a raft to drift from city A to city B?

10. A, B, C, 3 test tubes each have 10 grams of water, 20 grams, 30 grams, pour 10 grams of saline of a certain concentration into A, take out 10 grams and pour it into B after mixing, and then take out 10 grams and pour it into C, at this time, the concentration of saline in C is, what is the concentration of brine in A at the earliest? Wish!

Another 1/4 plus.

Add 3 and 3/7 and 4/7) (2 and 1/8 2/2 = (10+10)*1+0

2014 3/7 8/8 2/7 14 5/13 = 2+

Set a to take x yuan.

1-2/5)x=(1-1/10)(300-x)x=180

So A takes $180 and B gets $120.

Let's say there are x tons of cement in total.

A (2 5) x+14

B x - A = (3 5) x - 14

Because car B transports one-quarter more than car A

3/5)x-14 =[(2/5)x+14](1+1/4)x=315

A transported 315x(2 5)+14=140

Question 1=

Question 2 = (3/7 + 6 and 4/7) * (

20 Question 3 = 14 * (3/7 2/7) + 8/8 + 5/13) = 14 * 1/7 +

Question 4 A has 3 5 left, B has 9 10 left, and the two of them have the same amount of money left, so A's money is more than B's money 9 10 3 5 = 3 2

Then A gets 300*3 5=180 B gets 300*2 5=120 Question 5 Let the total number be x tons Then car A transported 2 5x+14, and car B transported (2 5x+14)*(1+1 4)=1 2x+35 2

Then x=2 5x+14+1 2x+35 2 gives x=315

1: The computer comes with a calculator).

2: 20 (simplify).

3: Simplify).

4: A180; B120; (Column Equation for Unknowns) 5:225 (Column Equation for Unknowns).

Doing Olympiad math is very helpful for being admitted to key schools, don't rely on others, otherwise it will be useless.