A series, starting from the second number, the difference between each number and the previous number is a definite number. This series is called arithmetic progression, and this constant is called tolerance. For example:
( 1) 1、2、3、4、5、……99、 100 (2) 1、3、5、7、9、……97、99
(3)4、 10、 16、22、28……82、88
The above three series are arithmetic progression, the tolerance of series (1) is 1, the tolerance of series (2) is 2, and the tolerance of series (3) is 6. Each number in a series is called an item of the series, the first number is called the first item, the second number is called the second item, and so on. If the number of projects in a series is limited, we call the first project the first project and the last project the last project.
Sum of arithmetic progression = (the first term+the last term) × number of terms ÷2 The last term = the first term+tolerance × (number of terms-1).
First Material = Last Material-Tolerance× (MaterialNo.-1) MaterialNo. = (Last Material-First Material) ÷ Tolerance+1
Example11+3+5+7+...+1997+1999 =? In Example 2, the first item is 5 and the last item is 155.
Arithmetic progression sum of item 5 1.
There are 60 numbers in Example 3. The first number is 7, which comes from the sequence 3, 8, 13, 18. ...
Starting with the second number, how much is the last number more than the previous item 80?
If a number is greater than 4, find the sum of these 60 numbers. Example 5 3+7+ 1 1+...+99 =?
Example 6 A arithmetic progression whose term is 15, and the last term is 1 10 with a tolerance of 7. What's the sum of this arithmetic progression?
Profit and loss problem in five years (three years)
1, a tree planting team to plant trees. If each person plants 5 trees, there are still 14 seedlings left; If each race has seven trees, there will be a shortage of four seedlings. How many people are there in this group? A * *, how many seedlings?
The school bought some basketballs and distributed them to all classes equally. If each class is divided into four, it is14; If each class is divided into five, it's just over. How many basketballs did the school buy? How many classes are there?
The kindergarten class in Yan Xi Street distributes apples to the children. If everyone is divided into six parts, 72 parts are missing; If everyone is divided into four parts, it's just over. Find out the number of children in this kindergarten class and the total number of apples distributed.
4, a workshop production plan, scheduled to produce a number of parts. If each group completes 16 pieces, it can exceed 6 pieces; If each group completes 15 pieces, it can be more than 2 pieces. How many parts does this workshop plan to produce? How many groups of workers are there?
5. Fourth grade 1 class, reward excellent students with pencils. If everyone wins 14, there will be19; If everyone wins 12, there will be 1 1. How many excellent students are there in this class? How many pencils are there?
Xiaohua leaves home for school at 7 o'clock every morning. Walk 60 meters per minute, 6 points late; If you walk 80 meters per minute, you can get to school three minutes earlier. How many minutes does it take to get to school from home on time? How far is Xiaohua's home from school?
7. Measure the height of the bridge with a rope. When the rope is folded in half, there is still 5 meters left when it is hoisted to the water surface, and when it is folded in three, there is still 2 meters left when it is hoisted to the water surface. Find the height of the bridge and the length of the rope.
The fifth grade exercise (4) is calculated according to the new definition.
In the math contest, there is a problem that requires operation according to the new definition. The characteristic of this kind of problem is that it specifies a new definition of operation symbols and a new operation order, and requires a new operation method according to the new definition. The questions calculated according to the new definition are both interesting and flexible. Although it is different from the mathematics knowledge in the textbook, we can answer it with what we have learned. The key to solve this problem is to correctly understand the definition and transform the problem into four well-known operations according to the newly defined relationship. Answering such questions helps to improve our observation ability, analysis ability, adaptability and calculation ability.
Example 1 2 3 = 2+22+222 = 246, 3 4 = 3+33+333 = 3702, ...
Calculation: (1) 3 2; (2)5 3; (3) 1 X= 123, and find x.
Example 2 is known as a ※ b = (a+b) × (a-b), and Example 3 stipulates that 1※4= 1×2×3×4.
Find the value of 20 ※ 15. 6※5=6×7×8×9× 10, then
(4※5)÷(6※3)=?
Example 4 stipulates that [a, b, c, d] = 9ab-cd, and Example 5 assumes that a*b represents four times of a minus b.
If [1, 2,3, X]=3, find the value of x. 3 times, that is, a * b = 4a-3b.
(1) calculation: (1.5 * 0.8) * 0.5;
(2) Given X*(5*2)=46, find x.
Example 6 if a > b, [A, b] = a; If a < b,
Then [A, b] = B. Try to find (1) [8,0.8];
(2){[ 1.9, 1.90], 1.9} Example 7 n is a natural number, and F (n) = 3n-2 is specified.
For example, f (3) = 3× 3-2 = 7. Try asking:
f( 1)+f(2)+f(3)+……+f( 100)
The value.
Example 8 If 1= 1! 1×2=2! 1×2×3=3! …… 1×2×3……× 100= 100!
Then 1! +2! +3! +……+ 100! The unit number of is ().
Exercises in the fifth grade math class in China (4) Return to the original question
1, there is a number, multiply by 5 MINUS 26, divide by 4, add 13, and finally get 29. What is the number?
2. The workshop will issue bonuses according to the workers' overcapacity. Give half of the total bonus to Party A, then give the remaining half to Party B, then to Party C, 80 yuan, Ding 7 yuan and finally to 4 yuan. How much is this bonus?
3. An old man said, "Add my age to 17, then divide it by 4, subtract 15, and multiply it by 10, which is exactly 100." How old is this old man?
4. there are two numbers, a and b, and the result of subtracting b from a is equal to 7; B plus a, then multiply a, then subtract a, and finally divide by a, the result is equal to a ... find the numbers a and B.
5. A peach seller took a basket of peaches to various stores to sell: in the first store, he tasted one first, and then bought the remaining half; In the second restaurant, I tasted one first and then bought the remaining half. When you get to the third place, try one first and buy the remaining half. At this time there are 35 peaches left in the basket. How many peaches are there in this basket?
6. Someone went out for a trip, and spent more than half of the 350 yuan on the trip. When he came back, he spent the remaining half, which was 130 less, leaving 285 at home. How much money did he bring with him on this trip?
7. Dongxing Machinery Factory has five workshops. It is planned to produce twice as many lathes this year as last year, resulting in 480 more lathes than planned. It is known that even if each workshop produces less 120 units, it can reach 800 units. How many lathes did this factory produce last year?
8. Add 1 to a certain number, subtract 2, multiply 3 and divide 4, and the result is 6. What is the number?
Fifth grade exercises (5) digital map.
A Pentagon, connecting its diagonals into one.
A five-pointed star (as shown on the right), a * * *, how many triangles are there?
Shape? Problems like this are the counting problems of graphs.
When counting, it is required not to repeat or omit.
Example 1 How many line segments are there in the picture below? Example 2 How many line segments are there in the picture on the right?
A B C D E
Example 3 How many triangles are there in the picture on the right? Example 4 How many triangles are there under the regular pentagon?
A
Eurobank
Washington D.C.
Example 5 Calculate the total number of squares in the figure below (). Example 6 Statistics There are () rectangles in the figure below.
20 12 what is the answer to the fifth grade Olympic mathematics?
Test questions and answers of the fifth grade math Olympics in primary school, (1)A,199199.1+09.91+kloc-0/= 65438.
b、 1995+ 1996+ 1997+ 1998+ 1999+2000+2006 5438+0+2002+2003+2004 = 19995。
(2) Suppose: 1, at most 23 people take part in Chinese and math competitions, at most 5 people take part in Chinese and English competitions, 15 people only take part in English competitions, and the other 7 people do nothing, so at most 28 people take part in two competitions at the same time. 2. Up to 20 people take part in Chinese and English competitions at the same time, and up to 8 people take part in Chinese and math competitions at the same time. 15 people only take part in math competitions, and the other 7 people do nothing, so up to 28 people take part in two competitions at the same time. Other hypotheses will also give answers to up to 28 people.
(3) The minimum sum of five consecutive natural numbers is 24, 25, 26, 27, 28, and the minimum sum is 130.
(4) It takes (1200+300)÷20=75 seconds for the train to get on and off the bridge.
(5) The sum of n consecutive even numbers should be 2+4+6+8+...= n× (n+ 1).
Then 2+4+6+8+...+1000 = 500× (500+1) = 250500.
(6) Fly in circular orbit for 2× (6400+343 )× 3.14×10 ≈ 420000 km.
2. residential area a.
_ _ _ _ _ _ _ _ _ _ s _ In the street is the _ _ _ _ _ _ _ _ _ milk station.
. Residential area b
3. As shown in the figure, the side length of the small square vacant in the middle is 5cm, and the width of the rectangular plate is
6 cm, and the area of the rectangular plate is 66 cm 2.
20 meters
3 1.5 m
4. As shown in the picture on the right, if the three roads are moved to the edge of the vegetable field, the vegetable growing area is a rectangular area with a length of 3 1.5m and a width of 20m, which is 630m2.
5. When the speed of the steamboat downstream is 440÷4= 1 10 (Li), the speed of the steamboat in still water is 1 10-45 = 65 (Li), and the speed of the steamboat returning from the coast is 65-25.
6, solution 1, from the meaning of the question, every six monks need six rice bowls, three vegetable bowls and two soup bowls, that is, 1 1 bowl, then 55 bowls are five times that of 1 1, and there are 6×5=30 monks. Scheme 2: Each monk should use a rice bowl, half a vegetable bowl and one third of a soup bowl, that is, * * * uses 1 16 bowls, and * * * has 55 monks +0 165438 = 30.
7. Solution 1, 240 sheep grazing for 6 days = original grass and new grass for 6 days = 1 sheep grazing 1440 days, 2 10 sheep grazing for 8 days = original grass and new grass for 8 days = 1 sheep grazing1. Grassland grass = 1 sheep eat 144 days of grass -6 days of new grass (1 sheep eat 72 days of grass) = 1 sheep eat 720 days of grass 18 days to eat the original pasture+18 days to grow new grass. Solution 2: The newly grown grass every day = 120 sheep can eat it on the same day, that is, no matter how long the grazing days are, special 120 sheep can eat the newly grown grass every day, so the number of sheep who eat the original grass in the pasture on 18 days+120 sheep (eat the newly grown grass on the same day
Grassland grass = 1 sheep grazing for 720 days =40 sheep grazing 18 days, and it takes 40+ 120= 160 sheep.
18 days can complete the original and newly grown grass in the pasture. Solution 3. This problem can also be solved by ternary linear equations. Assuming that the original grass in the pasture is A and the newly grown grass is B, C sheep can finish the original grass and newly grown grass in 18 days. Then a+6b = 240× 6 (1); A+8b=2 10×8 (2) Formula a+ 18b=c× 18 (3) Formula can solve the problem of c= 160 sheep.
8. Water fee this month =15× 0.8+10× 0.8× 2 = 28 yuan.
9. The number of trees to be used is 0.28× 20× 50000000 ÷ (3.14×10× 2000) ≈ 446 trees = 000400, and 0.0004 square kilometers of forest will be destroyed. Using disposable chopsticks destroys forests, pollutes the environment and causes ecological disasters. We should refuse to use disposable chopsticks to protect the forest and ecological environment, and suggest using sterilized bamboo chopsticks instead of disposable chopsticks.
The data in questions 10 and (1) can be made into bar, broken line and fan statistical charts. (2) The amount of municipal solid waste is increasing year by year, which shows that China's economy and society are developing rapidly and people's living standards are improving year by year; (3) There is so much garbage in China every year, 1) landfill is chosen for one-time treatment; 2) We should turn waste into treasure, establish a comprehensive garbage sorting plant, sort and recycle all kinds of useful industrial raw materials, and make fertilizers. Protect the ecological environment.
The area of 1 1 and (1) graphs is 90 square centimeters.
(2) Solution 1: As shown in the figure, the area of semicircle minus the area of triangle = the area of two pieces and a half.
=3.5625 square centimeters.
Then the shadow area of four leaves =
12813.5625× 4 =14.25 cm2
10 solution 2: the shadow area of four leaves = the area of four semicircles MINUS the conformal area.
= 39.25-25 =14.25 cm2
12, according to the meaning of the question: there are three cases where the three categories are (3,3,8 programs); (Schemes 3, 4 and 7) * * There are six situations; (Scheme 3, Scheme 5 and Scheme 6) * * There are six situations; (Schemes 4, 4 and 6) * * There are three situations; (4, 5, 5 program) There are three situations. These three categories have 3+6+6+3+3=2 1 expression.
13. Finally, we can get five squares with side lengths of 15cm, 6cm, 6cm, 3cm and 3cm respectively.
Math Olympics in the fifth grade of primary school: Tea 98. /Article/sort 09/sort 05 1/sort 088/INFO-554。
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The first four have answers. Look, you can download it. Very good. It's all free.
Who has 20 primary school fifth-grade Olympic math problems (with answers) fifth-grade Olympic math training problems
Class: Name: Score:
1, calculation problem
① 1993× 1994 1994+ 1994× 1993 1993 ② 19.58×66+22×9 1.26
2. One pen can be exchanged for three ballpoint pens, and four ballpoint pens can be exchanged for seven pencils, so four pens can be exchanged for () pencils.
3. Two people A and B, who are 260 kilometers apart, travel in opposite directions along a straight road at the same time, heading for B and A respectively. A driving 32 kilometers per hour. B travels 48 kilometers per hour. Party A and Party B each have a walkie-talkie. When the distance between them is less than or equal to 20 kilometers, they can contact each other through walkie-talkies. Q:
(1) How soon can two people start to communicate with each other by walkie-talkie?
(2) How long did it take them to meet after they contacted each other by walkie-talkie?
(3) How long can they contact each other on the walkie-talkie?
Next March 1 is Thursday, so next year's National Day is a week.
5. There are 40 consecutive natural numbers, and the maximum number is four times the minimum number, so the sum of the maximum number and the minimum number is _ _ _ _ _ _ _.
6. Three kittens went fishing. They caught 36 fish. Among them, the number of fish caught by black cats and flower cats is five times that of white cats, and the number of fish caught by flower cats is two times less than that of the other two cats, with nine fewer fish. A black cat can catch _ _ _ _ fish.
7. In the formula shown below, if the numbers in the seven squares are different from each other, then the maximum sum is _ _ _ _ _. ( 176)
8. Arrange several natural numbers starting from 1 into the shape shown in the figure above. So, the second number from the left in line 25 is.
9. On Sunday morning, Xiaoming found that the alarm clock had stopped because the battery was dead. He installed a new battery, estimated the time and set the hands of the alarm clock to 8 o'clock. Then, Xiaoming left home and went to the planetarium. Xiaoming arrived at the planetarium and saw that the standard clock of the planetarium showed 9: 15. An hour and a half later, Xiao Ming returned home from the planetarium at the same speed. The time to see the alarm clock is 1 1: 20. When should Xiaoming set the alarm clock accurately? time division
10. Teacher Zhang is three times as old as Bing Wang and four years younger. Teacher Zhang's age seven years ago is the same as that of Wang Bing nine years later. How old are Teacher Zhang and Bing Wang?
1 1, car A and car B leave from A and B at the same time, meet after 4 hours, and car A will walk to B for another 3 hours. It is known that car A is 20 kilometers faster than car B every hour. How many kilometers is it between A and B?
12, 54 people in the class went boating, and one * * * took a boat on 10, including 6 people in the big boat and 4 people in the small boat. How many ships are there?
1. Simple calculation:
13 4.36× 12+88×4.36
14 14. 15+ 12.04×99-2. 1 1
15 7. 1×399.08
16 75×4.67+ 19.9×2.5
17 2005 65438+ 10/is Saturday. What day is Children's Day this year?
Quotient 18 4÷ 1 1 What is the 2008th place after the decimal point?
What is the sum of 19 8÷ 1 1 quotient after the decimal point?
20. Move the decimal point of a number one place to the left, and then add it to this number, and the number is 17.27. What is the number?
2 1. If the decimal point of a number is moved one place to the right, the value is 86.4 larger than the original value. What is the original number?
22. Complement the decimal point in the incomplete number sum product in the multiplication formula.
□.□□
×□ 2.□
□ □ □
□□□ □
__□ 8□
□□ 9□ 2 □
The sum of the ages of A, B and C is 1 13 years old. When A is half the age of B, C is 38 years old. When B is half the age of C, A is 17 years old. So how old is B now?
Who has the answer to the fifth-grade olympiad, urgent ... the fifth-grade mathematical Olympics.
fill-in-the-blank question
1. Calculation: 0.02+0.04+0.06+0.08+…+19.94+19.96+19.98 = _ _ _ _ _.
2./kloc-0 /×1+2× 2+3× 3+...1997×1998×1998 is _ _ _ _ _
3. A two-digit number, add a 0 between its two digits, which is 630 more than the original number. Such two digits are _ _ _ _ _.
At present, there are four RMB 1, two RMB 2 and three RMB 10. If you take at least 1 piece and at most 9 pieces, then * * * can be made into _ _ _ _ _ _.
5. A set of four digits, each of which is not 0 and different from each other, but the sum of all digits of each digit is 12. Put these four numbers in descending order, and the 25th place is _ _ _ _ _ _ _ _.
6. The big monkey gives the little monkey peaches. If each monkey gets 8 peaches, there are 10 peaches left. If each little monkey is divided into 9 peaches, then a little monkey will be divided into less than 9 peaches, but it can still be divided into peaches, small ones.
8. There is a residential building, and each family subscribes to two different newspapers. This residential building subscribes to three newspapers. Among them, there are 34 Nantong radio and television newspapers, 30 Yangzi Evening News and 22 newspaper abstracts. Then, Yangzi Evening News and Newspaper Digest have _ _ _ _ _ _ subscribers.
9. Qiang Qiang and Fang Fang run back and forth in a straight line, with a distance of 120 meters. Qiang Qiang runs 2 meters per second and Fang Fang runs 3 meters per second. If two people start from both ends at the same time, then * * * meets _ _ _ _ times in 15 minutes.
10. A workshop has processed a batch of parts and plans to process 48 parts a day. Actually, 12 pieces were processed more than planned every day, and the task was completed 5 days ahead of schedule. This batch of parts * * * has _ _ _ _.
(Adapted from the 427 issue of "Decimal Newspaper")
1 1. The sum of the ages of Li, Sun and Wang this year is 1 13 years old. When Wang was 38 years old, Sun was twice as old as Li. When Li 17 years old, Wang was twice as old as Sun. Sun is _ _ _ _ _ _ _ _ years old this year.
(Decimal newspaper 492,98-9-18)
(Decimal Report 475)
13. There are 16 locks and 20 keys, of which 16 and 16 of 20 keys are paired one by one, but now the locks and keys are confused. Then, you need to try at least _ _ _ _ times to make sure that the lock and key match.
(Decimal newspaper 457, adapted)
(adapted from decimal newspaper 475,98-4 98-4- 10/0)
15. Four students, A, B, C and D, participated in the math competition for primary school students in Nantong. Before the competition, three teachers made predictions:
A teacher said: C first, A second;
Another teacher said: B is the first and D is the fourth;
There is also a teacher: Ding comes second and C comes third.
When the results were announced, it was found that the predictions of the three teachers were only half right. Please infer the result of the competition: the first place is _ _ _ _ _, the second place is _ _ _ _ _, the third place is _ _ _ _ _ _, and the fourth place is _ _ _ _ _ _.
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Who has the Olympic Games problem in the fifth grade of primary school? There is an answer. fill (up) a vacancy
1. Calculation: 0.02+0.04+0.06+0.08+…+19.94+19.96+19.98 = (099.009).
2. The unit number of1×1+2× 2+3× 3+...1997×1997+1998 is (9).
3. A two-digit number, with a 0 between its two digits, is 630 more than the original number, and there are (10) such two digits.
4. At present, there are 4 RMB 1, 2 RMB 2 and 3 RMB 10. If you take out at least 1 sheet and at most 9 sheets, then * * * can make (56) different amounts of money.
5. A set of four digits, each digit is not 0 and different from each other, but the sum of all digits of each digit is 12. Arrange all the four numbers from small to large, and the 25th number is (5 124).
6. The big monkey gives the little monkey peaches. If each monkey gets 8 peaches, there are 10 peaches left. If each monkey is divided into 9 peaches, then a monkey will be divided into fewer than 9 peaches, but it can still be divided into peaches. How many monkeys are there (18)?
7. There is a residential building, and each family subscribes to two different newspapers. Residential buildings subscribe to three newspapers. Among them, there are 34 Nantong radio and television newspapers, 30 Yangzi Evening News and 22 newspaper abstracts. In addition, there are 26 subscribers to Yangzi Evening News and Newspaper Digest.
8. Qiang Qiang and Fang Fang run back and forth in a straight line, with a distance of 120 meters. Qiang Qiang runs 2 meters per second and Fang Fang runs 3 meters per second. If two people start from both ends at the same time, they will encounter * * * (7) times in 15 minutes.
9. A workshop processes a batch of parts, and it is planned to process 48 pieces per day, but actually it processes 12 pieces more than planned. As a result, the task was completed five days ahead of schedule. There are (300) parts in this batch.
10. A four-digit number has four different numbers, and none of them is zero. The sum of these four numbers is 12, so there are (48) such four digits * * *?
1 1.A Project A can be completed by one person for 63 days, and then by B for 28 days; If both parties cooperate, it will take 48 hours. Now A does it alone for 42 days, and then B does it alone. How many days will it take to finish it? It takes X days for Party A to complete it alone, and Y days for Party B to complete it alone. If the engineering quantity is set to 1, the formula can be: 63/x+28/y = 1 48 (1/x+1/y) =1,and x can be solved.
12. A tree planting team went to plant trees. If each person plants 5 trees, there are still 14 seedlings left; If each race has seven trees, there will be a shortage of four seedlings. How many people are there in this group ((14+4)/2=9)? A * * * has (5*9+ 14=59) seedlings?
13. The school bought some basketballs and distributed them to all classes equally. If each class is divided into four, it is14; If each class is divided into five, it's just over. Did the school buy (4*4+ 14=30) basketballs? There are (4*4= 16) categories?
-
Calculation: 0.02+0.04+0.06+0.08+…+19.94+19.96+19.98 = (099.009).
2. The unit number of1×1+2× 2+3× 3+...1997×1997+1998 is (9).
3. A two-digit number, with a 0 between its two digits, is 630 more than the original number, and there are (10) such two digits.
4. At present, there are 4 RMB 1, 2 RMB 2 and 3 RMB 10. If you take out at least 1 sheet and at most 9 sheets, then * * * can make (56) different amounts of money.
5. A set of four digits, each digit is not 0 and different from each other, but the sum of all digits of each digit is 12. Arrange all the four numbers from small to large, and the 25th number is (5 124).
6. The big monkey gives the little monkey peaches. If each monkey gets 8 peaches, there are 10 peaches left. If each monkey is divided into 9 peaches, then a monkey will be divided into fewer than 9 peaches, but it can still be divided into peaches. How many monkeys are there (18)?
7. There is a residential building, and each family subscribes to two different newspapers. Residential buildings subscribe to three newspapers. Among them, there are 34 Nantong radio and television newspapers, 30 Yangzi Evening News and 22 newspaper abstracts. In addition, there are 26 subscribers to Yangzi Evening News and Newspaper Digest.
8. Qiang Qiang and Fang Fang run back and forth in a straight line, with a distance of 120 meters. Qiang Qiang runs 2 meters per second and Fang Fang runs 3 meters per second. If two people start from both ends at the same time, they will encounter * * * (7) times in 15 minutes.
9. A workshop processes a batch of parts, and it is planned to process 48 pieces per day, but actually it processes 12 pieces more than planned. As a result, the task was completed five days ahead of schedule. There are (300) parts in this batch.
10. A four-digit number has four different numbers, and none of them is zero. The sum of these four numbers is 12, so there are (48) such four digits * * *?
1 1.A Project A can be completed by one person for 63 days, and then by B for 28 days; If both parties cooperate, it will take 48 hours. Now A does it alone for 42 days, and then B does it alone. How many days will it take to finish it? It takes X days for Party A to complete it alone, and Y days for Party B to complete it alone. If the engineering quantity is set to 1, the formula can be: 63/x+28/y = 1 48 (1/x+1/y) =1,and x can be solved.
12. A tree planting team went to plant trees. If each person plants 5 trees, there are still 14 seedlings left; If each race has seven trees, there will be a shortage of four seedlings. How many people are there in this group ((14+4)/2=9)? A * * * has (5*9+ 14=59) seedlings?
13. The school bought some basketballs and distributed them to all classes equally. If each class is divided into four, it is14; If each class is divided into five, it's just over. Did the school buy (4*4+ 14=30) basketballs? There are (4*4= 16) categories?
Supplement to the question: 14. One pen can be exchanged for three ballpoint pens and four ballpoint pens can be exchanged for seven pencils, so four pens can be exchanged for (2 1) pencils.
The problems and answers of the Olympic Games in the fifth grade of primary school! fill-in-the-blank question
1. Calculation: 0.02+0.04+0.06+0.08+…+19.94+19.96+19.98 = (099.009).
2. The unit number of1×1+2× 2+3× 3+...1997×1997+1998 is (9).
3. A two-digit number, with a 0 between its two digits, is 630 more than the original number, and there are (10) such two digits.
4. At present, there are 4 RMB 1, 2 RMB 2 and 3 RMB 10. If you take out at least 1 sheet and at most 9 sheets, then * * * can make (56) different amounts of money.
5. A set of four digits, each digit is not 0 and different from each other, but the sum of all digits of each digit is 12. Arrange all the four numbers from small to large, and the 25th number is (5 124).
6. The big monkey gives the little monkey peaches. If each monkey gets 8 peaches, there are 10 peaches left. If each monkey is divided into 9 peaches, then a monkey will be divided into fewer than 9 peaches, but it can still be divided into peaches. How many monkeys are there (18)?
7. There is a residential building, and each family subscribes to two different newspapers. Residential buildings subscribe to three newspapers. Among them, there are 34 Nantong radio and television newspapers, 30 Yangzi Evening News and 22 newspaper abstracts. In addition, there are 26 subscribers to Yangzi Evening News and Newspaper Digest.
8. Qiang Qiang and Fang Fang run back and forth in a straight line, with a distance of 120 meters. Qiang Qiang runs 2 meters per second and Fang Fang runs 3 meters per second. If two people start from both ends at the same time, they will encounter * * * (7) times in 15 minutes.
9. A workshop processes a batch of parts, and it is planned to process 48 pieces per day, but actually it processes 12 pieces more than planned. As a result, the task was completed five days ahead of schedule. There are (300) parts in this batch.
10. A four-digit number has four different numbers, and none of them is zero. The sum of these four numbers is 12, so there are (48) such four digits * * *?
1 1.A Project A can be completed by one person for 63 days, and then by B for 28 days; If both parties cooperate, it will take 48 hours. Now A does it alone for 42 days, and then B does it alone. How many days will it take to finish it? It takes X days for Party A to complete it alone, and Y days for Party B to complete it alone. If the engineering quantity is set to 1, the formula can be: 63/x+28/y = 1 48 (1/x+1/y) =1,and x can be solved.
12. A tree planting team went to plant trees. If each person plants 5 trees, there are still 14 seedlings left; If each race has seven trees, there will be a shortage of four seedlings. How many people are there in this group ((14+4)/2=9)? A * * * has (5*9+ 14=59) seedlings?
13. The school bought some basketballs and distributed them to all classes equally. If each class is divided into four, it is14; If each class is divided into five, it's just over. Did the school buy (4*4+ 14=30) basketballs? There are (4*4= 16) categories?
If the minimum number is x, the maximum number is (39+x).
39+x=4x x= 13
The maximum quantity is 52.
The total is 65