Xiaoshengchu mathematics application problem

Composite application problem 2

Solving application problem 4 with column equation

Solving application problem 6 with proportional knowledge

Basic problems of fractional application problems 8

Basic exercise 10

Comparison and variant exercise 12

Simple application problem

First, various quantitative relations.

In addition to sum, difference, product and quotient, the quantitative relations involved in simple application problems also include the following common quantitative relations:

Income-expenditure = balance unit price × quantity = total price × speed × time = distance

Single output × quantity = total output efficiency × time = total working capital × interest rate × time = interest.

Second, basic training.

Group a

1, fill in the blanks.

(1) Simple application problems must have two () and one (), and the relationship between them can be summarized into four types: (), (), () and ().

(2) Knowing the speed and time of a car, you can get (). If you want to get the speed of this car, you must know () and ().

(3) To calculate the interest on the deposit in the bank, you need to know how much the principal is, as well as () and ().

(4) Knowing the number of walnut trees and the kilograms of harvested walnuts, finding the yield of each walnut tree is the problem of finding ().

(5) It is known that three dairy sheep can produce 2340 kilograms of milk a year, and you can get ().

2. Answer the following application questions.

(1) A rope is 35 meters long. Need 14.75 meters. How many meters are left?

(2) A car travels 25 kilometers in 0.5 hour, 1 hour. How many kilometers?

(3) Two fifths of a batch of goods have been shipped. How many parts are left?

(4) There are 50 students in a class, and the attendance rate today is 96%. How many people are present today?

(5) There are 85 peach trees in the orchard, and the number of pear trees is exactly four times that of peach trees. How many pear trees are there?

(6) The canal with a total length of 1.200m has been repaired for 450m. How many meters can I finish?

(7) The school buys 18 football and spends 1.89 yuan. How much is each football?

(8) Among the 50 students in class 6/kloc-0, 48 students participated in various "interest groups" activities. What percentage of the class participated in the "interest group" activities?

(9) The construction team has completed a section of highway, with a total length of 8.4 kilometers, accounting for 80% of the total length. How many kilometers is this road?

Group b

1, fill in the blanks as required.

A kind of clothing, the original price of each set of 85 yuan, the current price is 4/5 of the original price, how much is each set now?

Analysis:

(1) The known conditions are () and (), but the problem is ().

(2) As the original price of this kind of clothing is in 85 yuan, the current price is 4/5 of the original price. What is the current price, that is, 4/5 of ().

(3) Find the fraction of a number and calculate it by the method of ().

2. What two conditions do you need to know about the following questions?

(1) How many students are there in Class 6 * * * Class 1 (1)? (2) How many more boys are there than girls in Class Six (1)?

(3) How many fewer peach trees are there than pear trees in the orchard? (4) How much does the average fifth grader donate to the disaster area?

(5) How many kilometers does the car travel per hour on average? (6) How many times as many people are there in the chorus as in the dance team?

(7) Compared with the sixth grade, what is the donation amount?

(8) How many hours should the remaining books be bound? (9) How long can Xiao Ming walk from home to school?

(10) How many days did this coal burn?

3. Complete the relevant quantitative relationship according to the conditions of the following questions.

(1) The number of the school dance team is 2/5 of that of the chorus.

() ⊙()= 2/5()○()= the number of dancers.

() ○ () = the number of members of the chorus.

(2) 125% of the plan actually completed.

() ⊙()= 125%()○ 125% = actual output.

() ○ 125% = planned output

4. A primary school planned to donate 700 yuan to Project Hope, and actually donated 840 yuan. What percentage of the plan is the actual donation?

Group c

1. Answer the supplementary conditions again.

(1) apples are less than pears15kg. How many kilograms of pears are there?

(2) A batch of goods used 4.5 tons. How many tons did this batch originally have?

(3) The number of boys in class 5/kloc-0 is 3/5 of that of girls. How many boys are there?

(4) Chicken is 2/3 of that of duck. How many chickens are there?

(5) In the "Civilization and Politeness Month" activity, the fifth grade did 75 good deeds, and how many good deeds did the second grade do?

2.( 1) An excavator digs 60 tons per hour. How many tons can you dig in 8 hours?

(2) Adapting this problem into the application of working hours.

Composite application problem

First, the general steps to solve application problems.

1, find out the meaning of the problem, and find out the known conditions and problems;

2. Analyze the relationship between the quantities in the problem, determine what counts first, then what counts ... Finally, what is important;

3. Determine how to calculate each step, list formulas and work out numbers;

4. Test and write the answers.

Second, basic training.

Group a

1, fill in the blanks as required.

The school bought 35 boxes of colored chalk, 45 boxes of white chalk more than colored chalk. How many boxes of chalk did you buy?

(1) Think from the point of view:

To ask a * * * how many boxes of chalk to buy, you must know () and (). The number of boxes of chalk in the question () is not directly given, so you must ask clearly first.

Step 1: Calculate first.

Step 2: Recalculate.

(2) Thinking from the known conditions:

Known as "bought 35 boxes of colored chalk, bought 45 boxes of white chalk more than colored chalk", you can know (), and you can calculate how many boxes of chalk a * * * bought by adding the number of boxes of ().

2. Answer the following application questions.

(1) Changsheng Farm wants to harvest wheat 16.4 hectares, which has been harvested for 3 days, with a daily output of 1.8 hectares. If you harvest 2.2 hectares a day from the fourth day, how many days will it take to harvest the remaining wheat?

(2) The 120 tons of coal shipped from the canteen has been burned for 40 days, burning 1.2 tons every day, and the remaining 30 days will be burned out. How many tons are burned on average every day?

(3) A class has 150 science and technology books, and 50 story books are twice as few as science and technology books. How many story books are there?

(4) Five crushers can crush 37.5 tons of feed in 3 hours. According to this calculation, how many tons of feed can 12 identical pulverizers crush per hour? xkb 1.com

(5) Bus A and Bus B start from two cities 600 kilometers apart. Car A travels 65 kilometers per hour, and car B travels 55 kilometers per hour. A few hours after departure, two cars met.

(6) Two warships A and B set out from two ports respectively. Ship A travels 42 kilometers per hour and ship B travels 38 kilometers per hour. The second ship leaves at 1 hour, and the first ship leaves. Four hours later, the two ships met. How many kilometers are the two ports apart?

(7) Zhang Mingjia used to use 28 tons of water every month. With the water-saving faucet, the water used in one year can now be used for two more months. How many tons of water are used every month now?

(8) There is a barrel of oil, 2/5 of which has been used, and there is 48kg left in the barrel. How much does this barrel of oil weigh?

(9) A factory burned coal 120 tons in April, which was less than that in March 1/9. How many tons of coal were burned in March?

(10) Students actively contribute their love to Project Hope. Class 6 1 donated to 96 yuan, while Class 62 donated more to 4 yuan than Class 6 1. What percentage did they donate?

(1 1) There are 45 tons of cement in the construction site. Use 1/5 of the gross tonnage for the first time and 1/3 of the gross tonnage for the second time. How many tons do you need for two times?

(12) A garden factory planted 4,500 trees last year, and plans to plant 20% more trees this year than last year. How many trees do you plan to plant this year?

(13) The actual investment of a project is 565,438+ten thousand yuan, which is less than the planned investment 15%. How much do you plan to invest?

(14) 80 young pioneers planted trees in 62 experimental primary schools, and 2 trees died, so as to seek the survival rate of planting trees.

(15) Aunt Zhang bought 5,000 yuan of three-year treasury bonds with an annual interest rate of 3.85%. How much interest will she get after three years?

(16) On Teacher's Day this year, Miss Li deposited 2,000 yuan in the bank for two years, with an annual interest rate of 2.43%. What is the principal and interest due to him? After deducting 20% interest tax, what is his principal and interest?

Group b

1. Which of the following statements is true?

(1) A highway maintenance team needs to build a road with a length of 2 100 meters. In the first five days, an average of 240 meters was repaired every day, and the remaining tasks were completed in three days. How many meters will be repaired on average every day?

①2 100-240×5÷3 ②(2400-240)÷3 ③(2 100-240×5)÷3

(2) A bookbinding team has to bind 2640 books, and 240 books have been bound in 3 hours. According to this calculation, how many hours will the remaining books be bound?

①(2640-240)÷240 ②2640÷(240÷3) ③(2640-240)÷(240÷3)

(3) A tractor team plowed 6.8 hectares of cotton fields for 4 days. According to this calculation, how many days will it take to plow 13.6 hectares of cotton field?

① 13.6÷(6.8÷4) ② 13.6÷(6.8÷4)+4 ③( 13.6+6.8)÷(6.8÷4)

(4) A road construction team laid a section of railway, originally planned to lay 3.2km every day, which was completed in 15 days. In fact, 0.8 kilometers more than originally planned is paved every day. How many days has this railway been paved?

①3.2× 15÷0.8 ②3.2× 15÷(3.2-0.8) ③3.2× 15÷(3.2+0.8)

(5) A chemical plant uses 14 tons of raw materials every day after adopting new technology. In this way, the raw materials used for 7 days can now be used for 10 days. How many tons of raw materials does this factory save every day compared with the past?

① 14×7÷ 10- 14 ② 14× 10÷7- 14 ③ 14- 14× 10÷7 ④ 14- 14×7÷ 10

2. Answer the following application questions.

(1) Master Wang originally planned to produce 28 toy cars every day on 15. In fact, two more toy cars are produced every day than originally planned. How many days do you actually need to finish the task?

(2) The cargo ship Huanghe sailed 85 kilometers from Port A to Port B, which is just 5/7 of the waterway between Port A and Port B ... How far is this cargo ship from Port B?

(3) A pile of sand is transported by car A alone for 8 times, and by car B alone for 10 times. If A and B are shipped together, how many times will the 9/ 10 of this pile of sand be shipped?

(4) The paving team paved a road, 2.5 kilometers per day, and walked 5/8 of the total length in 7 days. How many kilometers is this road?

(5) In the fifth grade, girls 12, which is equivalent to 2/3 of the number of boys. As a result, the number of winners accounted for 70% of the participants. How many winners are there?

Aunt Li wants to buy two bags of rice (35.4 yuan each),1meat from 4.8 yuan, vegetables from 6.7 yuan and1fish from 2.8 yuan. Aunt Li brought 100. Is that enough?

Group c

(1) The distance between the two places is 650km. After 2.5 hours, the two cars are still 400 kilometers apart. A few hours before the two cars met.

(2) The greening team originally planned to plant 768 trees in 8 days, but actually planted 32 more trees every day than originally planned. How many days does it actually take to complete this task?

(3) The road repair team built 66 meters on the first day, and the road repaired the next day was three times that of the first day. The third day is 30 meters less than the previous two days combined. How many meters were built on the third day?

(4) Fill the cup with water and pour the water into the kettle. After pouring 3 cups of water, the kettle weighs 0.85 kg. If you fill the kettle with 5 glasses of water, the weight of the kettle is 1.25 kg. How much does each glass of water weigh?

(5) Inventory steel 15 tons, accounting for 20% of the total for the first time and 1/2 tons for the second time. How many tons of steel are left?

(6) It takes 5 hours for Party A to complete a manuscript, and the work efficiency of Party B is 62.5% of that of Party A. How many hours does it take for Party B to complete this manuscript?

Solving application problems with column equations

First, list the steps of solving application problems by equations.

(1) Find out the meaning of the problem, find out the unknown, and express it with X;

(2) Find out the equal relationship between the quantities in the application problem and make an equation;

(3) solving the equation; (4) Test and write the answer.

Second, basic training.

Group a

1, tell the meaning of each formula.

(1) Students in Class One do a math problem A every day, denoted by 7a.

(2) Grade four students subscribe to China Youth Daily 120, which is x more than grade five, 120-x indicates. China Youth Daily costs one yuan each, 120a, (120-x) a) a.

(3) The side length of a square is one centimeter, denoted by 4a and denoted by a2.

(4) Teacher Zhang bought three volleyballs, each at X yuan, and paid the salesman 245 yuan, 245 -3x.

2, column equation to solve the following application problems.

The price of radio this year is 25% lower than last year. This year, the price of each radio is 36 yuan. How much did it cost last year?

(2) The price of a set of sportswear is 144 yuan, in which the price of trousers is 7/9 of that of coat. What's the price of pants?

(3) Distance between the two places 120km. Two people, A and B, start from two places by bike at the same time. A car runs every hour 14km. Four hours later, I met car B. What is the speed of car B?

Group b

1, find the equal relationship between the following quantities.

(1) There are seven more boys than girls in one class.

(2) The number of basketball is four times that of football.

(3) Pear trees 15 are three times more than apple trees.

(4) It costs more to buy three pens than five ballpoint pens 1.5 yuan.

(5) Two equal-length iron wires, one in a square and the other in a circle.

(6) Pear trees are just three-quarters of apple trees.

(7) Production of a batch of parts, some of which have already been produced, and the remaining 4500 pieces.

2. Complete the equation according to the meaning of the question.

(1) It took 15 days to build a canal with a length of 3,400 meters, and the remaining 1600 meters was left unattended.

= 1600 15x= =3400

(2) Xiao Zhang processes X parts per hour and Xiao Li processes 30 parts per hour. Two people work for 4 hours at the same time, and one * * * processes 232 parts.

=232 4x= =30×4

3. The column equation solves the following application problems.

(1) The canteen bought 175 kg of flour, and 25 kg was more than three times that of corn flour. How many Jin of corn flour did you buy in the canteen?

(2) The master processes more 162 parts than the apprentice. It is known that the number of parts processed by the master is four times that of the apprentice. How many parts are processed by the master and the apprentice respectively?

(3) Four pens are more expensive than 15 ballpoint pens in 7.6 yuan. The price of each ballpoint pen is 2.8 yuan. How much is each pen?

(4) The area of a triangle is 18cm2, its base length is 12cm, and its height is how many centimeters?

4. Choose an appropriate method to answer the following two questions.

(1) The number of girls in the school science and technology group is 18, which is two less than that of boys. How many boys are there in the school science and technology group?

(2) There are 36 girls in the school's science and technology group, with 3 times more boys and 6 more girls. How many boys are there in the school science and technology group?

Group c

Choose the correct answer.

(1) Female students in the science and technology group 1 1, 2 times less than male students. How many boys are there in the science and technology group?

①2x-7 = 1 1② 1 1-2x = 7③2x+7 = 1 1④2x- 1 1 = 7

(2) There are 80 more apricot trees in the orchard than peach trees, and the apricot trees are three times as many as peach trees. How many peach trees are there?

①3x-x=80 ②3x+x=80

2, column equation to solve the following application problems.

(1) has two barrels of oil, and the weight of barrel A is 1.2 times that of barrel B. If 5 kg of oil is poured into barrel B, the two barrels of oil are equally heavy. How many kilograms are there in two barrels of oil?

(2) The store bought 250 tons of cabbage, and 30 tons was less than 5/6 of radish. How many tons of radish did you buy?

(3) The road construction team built a road. On the first day, it covered the whole length of 1/5. On the second day, it covered 3/4 kilometers, leaving 2.05 kilometers. How many kilometers is this road?

Solving application problems with proportional knowledge

First, basic training

Group a

1, fill in the blanks.

(1) A farmer harvested 165 hectares of wheat in three days. According to this calculation, how many hectares of wheat can he harvest in eight days?

Analysis:

① The two quantities related to the problem are () and ().

(2) "According to this calculation" means that () is certain.

(3) The two related quantities in the problem are directly proportional to ().

4 Solution: Set.

⑤ Column proportion formula:.

(2) A car travels from A to B at a speed of 80 kilometers per hour and arrives in 5 hours. If it takes 4 hours to get there, how many kilometers do you need to drive per hour?

(1) in this problem is certain, and it is proportional to the relationship. So the sum of the two exercises is equal.

2 Solution: Set.

③ The column equation is:

2. Answer the following application questions.

(1) There are 800 exhibits in the school painting and calligraphy festival. Among them, the ratio of art exhibits to calligraphy exhibits is 5: 3. How many pieces are there in each of the two exhibits?

(2) Xiyingmen Hotel wanted to recruit a group of waiters according to the ratio of male to female of 3: 5, and as a result, it recruited 48 people, including how many waitresses?

(3) The actual distance between A and B is 120km. What is the distance between the two cities on the map with the scale of 1: 4000000?

(4) On the map of China with the scale of 1: 4000000, the distance from Beijing to Shaoshan is 35cm. What is the actual distance from Beijing to Shaoshan?

(5) The ratio of male to female teachers in an experimental primary school is 2∶5. There are 35 female teachers and how many male teachers are there?

(6) Prepare pesticides, and the ratio of drug to water is 1: 150.

① How many kilograms of medicine and water does it take to prepare 755 kilograms of this pesticide?

(2) There are 3 kilograms of medicine. How many kilograms can this pesticide be matched?

(3) If there is 525 kilograms of water, how many kilograms of medicine should be put in the preparation of this pesticide?

(7) A loom can weave 24 meters in 4 hours. According to this calculation, how many hours does it take to weave 54 meters?

(8) Wang Gang walks 60 meters from home to school, 15 minutes can walk to school. If you walk 75 meters per minute, how many minutes can you walk to school?

(9) The assembly team will assemble a batch of washing machines. It is planned to assemble 27 washing machines every day and complete the task in 20 days. Actually, 30 sets are assembled every day, and it only takes a few days to complete the task.

(10) To build a 208-meter-long pipeline, it will take 52 meters in the first five days. According to this calculation, how many days will it take to complete the pipeline?

(1 1) A canal was built in a village. It was originally planned to build 40 meters a day and complete it in 35 days. Results After completing the task in 25 days, how many meters were repaired on average every day?

Group b

1, students do exercises, with 20 people standing in each row, just standing in line 18. If there are 24 people in each line, how many people can stand?

A car travels 64 kilometers in 2 hours, and it takes 5 hours to travel from A to B at this speed. How many kilometers is the highway between A and B? (Fill in the blanks first, then use the proportional method to solve)

Because (), it is known that () of the car is certain, so the distance and time traveled by the car are directly proportional to ().

3. A TV factory accepted a batch of orders, and planned to install 400 sets every day, and the ordering task could be completed in 25 days. Now it requires 20 deliveries. How many days does it take to install every day? (Fill in the blanks first, then use the proportional method to solve)

Because () must be, () and () are in direct proportion.

4, a pile of coal, originally planned to burn 3 tons a day, can burn for 96 days. How many days can this pile of coal burn because it saves 0.6 tons a day by changing the stove?

5. It takes 2000 square bricks with a side length of 15cm to pave the floor of a classroom. How many pieces do you need if you replace it with a square brick with a side length of 25 cm?

Group c

1, 240 books, Xiaohong finished reading in 8 days 192 pages. According to this calculation, how many days will it take to finish reading the rest?

2. The road repair was originally planned to be completed in 15. In fact, 300 meters are built every day. The result was completed three days in advance. How many meters was originally planned to be built every day?

The production team produced a batch of parts. Originally planned 14 days, with an average of 1.500 parts per day. In fact, the number of parts processed every day is 2/5 more than originally planned. How many days did it actually take to complete this batch of processing tasks?

4. A car has 102 liters of oil in its fuel tank, and it consumes 8 liters of oil when running 56 kilometers. According to this calculation, how many kilometers can the remaining oil travel?

Someone walked 22.4 kilometers in 4 hours. At this rate, if you walk for another three hours, how many kilometers can a * * * walk?

6. Two cars, A and B, set off from two places 380 kilometers apart at the same time and met for 3 hours. It is known that the speed ratio of car A to car B is 10∶9. B How many kilometers did you drive when you met him?

7. There are 150 books in kindergartens in Le Tong, 40% of which are allocated to large classes, and the rest are allocated to small classes and middle classes according to the ratio of 4: 5. How many books are there in the small class and the middle class?

8. Two workshops 150 people. If 50 people are transferred from the first workshop, the number of people in the first workshop is 2/3 of that in the second workshop. How many people are there in workshop 2?

9. The price of a set of desks and chairs is 105 yuan, of which the price of chairs is 5/7 of that of desks. What's the price of this chair? (Answer with different knowledge)

10, Maple Leaf Garment Factory received the task of producing a batch of shirts. In the first five days, 600 shirts were produced, 40% of the task was completed. According to this calculation, how many days will it take to complete this task? (Answer with different knowledge)

Basic problems of fractional application problems

1 class and class 6 (4) have 20 boys and 30 girls. According to the above information, please ask at least 4% questions and answer them, and then think about the relationship between the questions. )

Question 1: Formula:

Question 2: Formula:

Question 3: Formula:

Question 4: Formula:

Question 5: Formula:

Question 6: Formula:

2. (1) There are 300 books in bookshelf A and bookshelf B * *, and the number of books in bookshelf A accounts for 60% of the total. How many books are there on shelf A?

(2) There are 180 books on shelf A, which is 60% of the total number of books in the two shelves. How many books are there on the two shelves?

(3) There are 300 books on shelves A and B, and the number of books on shelf A accounts for 60% of the total. How many books are there on the shelf?

(4) There are 120 books on shelf B. The number of books on shelf A is 60% of the total number of books on shelves A and B. How many books are there on shelves A and B?

(5) There are 300 books on shelves A and B, and the number of books on shelf A accounts for 60% of the total. How many books are there on shelf A than on shelf B?

(6) There are 60 more books on shelf A than on shelf B. It is known that the number of books on shelf A accounts for 60% of the total. How many books are there on shelves A and B?

(7) There are 180 books on shelf A, and the number of books on shelf B belongs to shelf A. How many books are there on shelves A and B?

(8) There are 300 books on shelves A and B. The number of books on shelf B belongs to shelf A. How many books are there on shelf A?

(9) There are 180 books on shelf A, and the number of books on shelf B is on shelf A. How many books are there on shelf A than on shelf B?

(10) There are 60 more books on shelf A than on shelf B. The number of books on shelf B belongs to shelf A. How many books are there on shelf A?

6. Uncle Wang went to the bank and deposited 20,000 yuan at an annual interest rate of 2.52%. How much interest will he get after three years? After deducting 20% interest, what is the after-tax principal and interest?

7. Student personal accident insurance's insurance amount is 5,000 yuan. Based on the annual insurance rate of 0.5%, how much insurance should Xiaohong Primary School pay after six years?

Basic exercises

1. There is a cup with 40 grams of water. Add10g sugar to find the sugar content.

2. There is a cup with 50g of sugar water, and the sugar content is 20%. How many grams of sugar and water are there?

3 3. 10/0g sugar is used to prepare syrup with sugar content of 20%. How many grams of water do you need?

4. In the oral arithmetic contest, Jane did it right 190 and wrong 10. What is the correct ratio?

5. In the verbal contest, Xiaozhen made 200 mistakes, and made 10 mistakes. What is the correct ratio?

6. In the oral arithmetic competition, Xiaozhen did 200 courses, with an error rate of 5%. How many courses did she answer correctly?

7. Once, the total score of a Chinese exam was only 70. What were the qualified and excellent scores?

8. There are 75 staff members in a public institution after downsizing, 45 fewer than before, and a few percent less?

9. Hangzhou Jiecentennial Celebration launched the clothing category "full 100 minus 50"; What is the minimum discount for clothing and cosmetics in the promotion of "cosmetics over 200 100"?

10, Lianhua supermarket can get a 15% discount when shopping with its membership card. Teacher Wang bought two boxes of drinks of a certain brand for the party, and he paid 6 1.75 yuan with his membership card. How much less than the original price?

1 1. For a project, it takes 8 days for Team A to do it alone, and it takes 12 days for Team B to do it alone.

(1) How many days will it take two teams to complete the project?

(2) Team A will do it for 2 days first, and the rest will be done by Team B alone. How many days will it take to finish it?

(3) Team B worked alone for three days, and the rest of the projects were completed by both teams. How many days will it take to complete this project?

(4) How many days will it take two teams to complete the whole project?

For a project of 12 and (1), it takes 10 days for Team A and Team B to work together, and 15 days for Team A to work alone. If Team B does it alone, how many days will it take to complete the project?

(2) A project is completed alone. Party A 15 days to complete, and Party B 30 days to complete, so cooperation began. Due to the need of work, Party A transferred midway, and as a result, Otsuichi took 16 days to complete. Team a was transferred for a few days.

13. There is a big round flower bed with a diameter of 20 meters on campus. How many square meters of turf should be laid on the flower bed? If the turf is 48 yuan per square meter, how much is it?

14. The outer diameter of bicycle wheel is 0.8m, and 1 min turns 70 times. How many meters can this bike advance in half an hour? (Keep integer)

15. Put three hoops around a cylinder with an outer diameter of 30m, and the joint of each hoop is 0.2m How long does it take to put these hoops?

16. The hour hand of the clock is 4 cm long and the minute hand is 5 cm long. Turn around separately. How many square centimeters did they sweep?

17. The hour hand of the wall clock is 5cm long and the minute hand is 8cm long. From 8 am to 2 pm, how many centimeters did the tip of the minute hand "walk" and how many square centimeters did the hour hand "sweep"?

18, (1) original price of a dress 100 yuan. 20% for the first time and 20% for the second time. What's the current price of this dress?

(2) The original price of a dress 100 yuan. The first price reduction is 20%, and the second price increase is 20%. What's the current price of this dress?

(3) The current price of a dress is 96 yuan after the first price reduction of 20% and the second price increase of 20%. What is the original price of this dress?

19. There are 500 employees in a factory, and the attendance rate on a certain day is 98%, of which 60% are female employees. How many girl employees are there on this day?

20. Warehouse A and Warehouse B * * * have 180 tons of grain. The grain in warehouse B is less than that in warehouse A. How many tons of grain are there in each warehouse?

21.In April, a store paid business tax at the rate of 5% 1.5 million yuan. What's the turnover in April?

22. The Xiao Wangs got back the money they deposited in the bank two years ago, with the principal and interest of * * * 4,662 yuan. Suppose the annual interest rate is 2.25% and the interest tax is 20%, then what is the principal of this deposit?

23. If a store sells a commodity at 10% of the marked price, it can still make a profit of 20%. If the purchase price of the goods is 1980 yuan, what is the bid price?

Contrast and variation exercises

1, (1) The books on shelf A belong to shelf B. If you take 2 1 book from shelf B, the number of books on the two shelves is equal. B How many books are there on the shelf?

(2) The books on shelf A belong to shelf B. If 2 1 books are taken from shelf B and put into shelf A, the books on the two shelves are equal. B How many books are there on the shelf?

2.( 1) There are 450 workers in Workshop A and Workshop B of a factory, of which Workshop A accounts for 36%. This year, Workshop A recruited another batch of workers, accounting for 40% of the total number of workers in the factory. How many people have been recruited this year?

(2) There are 450 workers in Workshop A and Workshop B of a factory, of which Workshop A accounts for 36%. Due to the need of work, a group of workers were transferred from workshop A to workshop B, and the number of workers in workshop A accounted for 30% of the total number of workers in the factory. How many people are there in Workshop A and Workshop B now?

3.( 1) There are 15 tons of steel in the warehouse. 20% of the total amount was used for the first time and 20% for the second time. How many tons of steel are left?

(2) There are 15 tons of steel in the warehouse. 20% of the total amount was used for the first time and the rest was used for the second time. How many tons of steel are left?

(3) There are 15 tons of steel in the warehouse. 20% of the total amount was used for the first time and tons were used for the second time. How many tons of steel are left?