Several problems of mathematics in the sixth grade of primary school .....

The sixth grade mathematics "percentage application problem" exercise volume

Class name score

1, 400 tons of wheat can grind out 340 tons of flour. What is the flour yield of this wheat?

2. Master Wang produced a batch of parts, 485 of which passed the inspection, and 5 failed/kloc-0. Find out the qualified rate of these products.

3. Class Six (1) has 48 students coming to class today, and two people have asked for leave to ask about the attendance rate of Class Six (1) today.

4. PLA soldiers were trained to shoot with live ammunition, and 50 people each fired 6 bullets. As a result, * * * hit 256 rounds, seeking the hit rate.

5. There are 25 boys in Class 5 (4), and all of them have reached the standard in physical education. Among the other 20 girls, 18 is up to standard, and the rate of class 5 (4) is sought.

6. For Xiao Wang's homework last week, 32 things were done right and 8 things were done wrong, so as to find the correct rate of Xiao Wang's homework last week.

Dongfeng Electric Meter Factory produced a batch of electric meters last month. Upon inspection,1225m is qualified and 25m is unqualified. Seek the qualification rate of these meters.

8. 40 workers in a workshop produce parts, and each person produces 10 parts per day. Only five failed. Find the qualified rate of this batch of parts.

9. Members of the Second Squadron planted 40 pine seedlings and 50 cypress seedlings. Results All pine seedlings survived and two cypress seedlings died. Seek the survival rate of these saplings.

10, 3,000 Jin of pears were shipped from the bazaar, and 40% of them were sold. How many kilograms are left?

1 1. The water pump factory produced 500 pumps in February, 20% more than that in February. How many pumps were produced in March?

12, a panda TV set, the original price is 2400 yuan, and now each set is 15% off. How much is each set now?

13, a pile of 50 tons of coal, 25% on the first day, the second day is the same as the first day, how many tons on the third day?

14, Xiao Chen read a book with 180 pages. He read 40% of the book in the first week, 25% in the second week, and how many pages did he read in two weeks?

15, the farm has to harvest 2000 square meters of rice, with 25% for the first harvest and 20% for the second harvest. How many square meters were harvested for the second time?

16, Xiaojun reads story books. On the first day, * * * read 42 pages, and the next day, * * * read 43 pages, and 83% of the whole book was still unread. How many pages does this story book have?

17, a workshop planned to produce 400 parts in June, and completed 40% in the first half of the year. Now, if the actual output exceeds 10%, how many parts must be produced in the second half of the year?

18, it takes 4 hours for Master Wang to process a batch of parts, and the working efficiency of Li Shifu is 20% higher than that of Master Wang. It only takes a few hours for two people to make this batch of parts together.

19. If an expressway has been built, it will be repaired for another 50 meters, and the remaining 10% of the total length will not be repaired. What is the total length of this highway?

20. A road maintenance team built a road. It was originally planned to build 300 meters a day, but actually it was built more than the original plan 12%. How many meters does it actually build every day?

2 1. Last year, 60 households in Hongxing Village planted rape, and each household produced an average of 105 kg of rape. The oil yield of rapeseed is 42%. How many Jin of rapeseed can this village fry last year?

There are 250 workers in the first workshop of a weaving factory, which is equivalent to the number of workers in the second workshop. The total number of workers in the two workshops accounts for 1 1% of the total number of employees. How many employees are there in the whole factory?

23, a wire, the first cut off 28% of the total length, the second cut off 8.8 meters, twice just cut off half of the total length. How many meters were cut off for the first time?

24. Two trains leave from cities A and B relatively simultaneously. After 2.4 hours, the distance between the two trains is 40% of the total length of the railway between the two cities. It is known that the speed of car A is 20% faster than that of car B, and the speed of car B is 45 kilometers per hour. What is the total length of the railway between the two cities?

25. A batch of rice was shipped from the grain store along the Yangtze River, which sold 35% in the morning and 20% in the afternoon. The remaining 75% was sold the next day, leaving 3690 kilograms two days later. How many kilograms is this batch of rice?

Shan Ye Machinery Factory produced 240 machines this year, 40 more than last year. What percentage has the output increased this year?

The sixth grade mathematics "percentage application problem" exercise book 4

Class name score

1, there is a refrigerator, the original price is 2000 yuan, and it is sold at a reduced price 1600 yuan, which is a few percent lower?

2. There is an air conditioner, the original price is 1600 yuan, but after the price increase, it sells for 2000 yuan, which is a few percent higher?

3. There is a TV with the original price of 1200 yuan, which is lower than that of 300 yuan. How much is the price reduction?

4. There is a disinfection cabinet, the original price is 2,400 yuan, and the price has increased by a few percent in 400 yuan.

Bright primary school had 24 basketballs last year, and bought 6 new basketballs this year. How many basketballs are there today? What percentage has this year increased compared with last year?

6. The original ticket for a park in 80 yuan will be 20% off during the National Day. How much can you save per ticket? What's the equivalent of a price reduction?

7. Nanshan Primary School covers an area of 8,000 square meters, of which the green area accounts for 65%, and the rest are teaching buildings and roads. What is the green area of Nanshan Primary School? How many square meters are there in the teaching building and road?

8. Shopping malls offer discounts, with 50% discount on clothes and 20% discount on stationery. How much does Xiao Ming actually spend on a dress with the original price of 320 yuan and a schoolbag with the original price of 120 yuan?

9. The germination rate of a batch of seeds is 98.5%. Sowing 3000 seeds, how many seeds may not germinate?

10. Last year, an orchard produced 4500 kilograms of apples. This year, due to the good climate, the output has increased by 20% compared with last year. How many kilograms of apples have been produced this year?

1 1. Girls in the sixth grade of experimental primary school account for 48.75% of the whole grade. What is the proportion of boys in the whole grade? If there are more boys than girls 12, how many are there in the sixth grade of experimental primary school?

12. The vegetable base produced 24,000 tons of vegetables this year, an increase of 20% over last year. What was the output of this vegetable base last year?

13,504 classes have 20 people who participate in art interest groups, 20% more than those who participate in sports interest groups. How many people join the sports interest group?

14. Uncle Wang deposited 4,000 yuan in the bank for 3 years, with an annual interest rate of 3. 15%. What's the interest payable? How much is uncle Wang's principal plus interest?

15, Xiaoming's electricity consumption in June was 180 kwh, 20% more than that in June. The electricity charge per kWh is 0.54 yuan. How much is Xiaoming's electricity bill in July? 〕

16, Linlin's father's total salary in 2000 was 13500 yuan, which was 240% higher than that in 200 1 year. What is Linlin's father's salary in 2006?

17, Xinhua Bookstore has a batch of new children's books. Those sold on the first day accounted for 40% of the total on the second day, leaving 400 copies. How many children's books are there in this batch?

18, a batch of parts, the first day of processing, the second day of processing is 25% more than the first day, and the processing in two days is less than 62.5% 400 of the total. How much is the extra task?

19, A and B cars * * * transported a batch of coal. When they finished, Car A transported 9 tons more than the total, and Car B transported 50% of the tonnage of Car A.. How many tons is this batch of coal?

20. If the road repair team builds a road, it will take 15 days for Team A to build a road alone, while Team B can build 44 meters every day. When the two teams build this road together, Team A will build 60% of the total length. How long is this road?

2 1, A, B and C produced a number of toys. A produced two pieces, B produced two pieces and C produced 240 pieces. How many toys are there in this batch?

Practice on the area of a circle

1.C=( ) = ( ) S=( ) =()。

2. Given the circumference of a circle, find d= () and r= ().

3. If the radius of a circle is enlarged by 2 times, its diameter, perimeter and area will be enlarged by () times.

4. Annular area s = ().

5. Draw a circle with a compass with a circumference of 50.24 cm. The distance between the two toes of the compass should be () cm, and the area of the circle drawn is () cm2.

6. The radius of a big circle is four times that of a small circle, the circumference of a big circle is () times that of a small circle, and the area of a small circle is () times that of a big circle.

7. The radius of the circle increases 1/4, the circumference of the circle increases (), and the area of the circle increases ().

8. The circumference of a semicircle is 20.56 decimeters, and the area of this semicircle is () square decimeters.

9. Divide a circle into 1000 identical small sectors, and cut it into an approximate rectangle with a circumference longer than the original one 10 cm. The area of this rectangle is () square centimeters.

10, draw the largest circle in a square with an area of 24 square centimeters, and the area of this circle is () square centimeters; Then draw the largest square in this circle, and the area of the square is () square centimeters.

1 1, the radius of the big circle is three times that of the small circle, and the area of the big circle is 84.78 square centimeters. What is the area of this small circle?

12, the radius of the big circle is twice that of the small circle, the area of the big circle is more than that of the small circle 12 cm2, and the area of the small circle is () cm2.

13. Find the circumference of the circle.

(1)r =4 decimeter (2) D = 6 cm.

14. Find the area of the circle.

(1) R = 3 decimeters (2) D = 8 cm.

(3) C = 12.56m (4)c semicircle =15.42m.

15. Judgment (tick "√" for the right and "×" for the wrong)

(1) The line segment passing through the center of the circle is called the diameter of the circle. ……………………( )

(2) The circumference is 3. 14 times the diameter of a circle. …………………………( )

(3) The radius is half of the diameter. ……………………………………( )

(4) The pi of any circle is 3. 14 .............................. ().

(5) The circumference of a semicircle is equal to 1/2 plus the diameter of the circle, so the area of the semicircle is equal to 1/2 plus the diameter of the circle. ( )

16. The radius of the outer circle of a ring is 8 decimeters and the radius of the inner circle is 5 decimeters. What is the area of this ring?

17. The circumference of the outer circle of the ring is 18.84 cm, and the diameter of the inner circle is 4 cm. What is the area of this ring?

18. The radius of the circular flower pond on campus is 6m. A cement road with a width of 1m will be built around the flower pond. What is the area of the cement road?

19.( 1) The diameter of the front wheel of the road roller is 1.2m, and it is rolled 6 times per minute. How many meters can 1 hour go forward?

(2) The outer diameter of bicycle tire is 7 1cm, and it rolls 100 times per minute. How many minutes does it take to cross a 1000 meter bridge?

Practice on the area of a circle

First, fill in the blanks.

(1) Divide a circle into several equal parts and cut it into an approximate rectangle. The length of this rectangle is equivalent to (), and the width of the rectangle is circular (). Because the area of a rectangle is () and the area of a circle is ().

(2) The diameter of the circle is 6 cm, the circumference is () and the area is ().

(3) The circumference of a circle is 25. 12 decimeter, and its area is ().

(4) The radius of circle A is three times that of circle B, the circumference of circle A is (), and the area of circle A is ().

(5) The radius of a circle is 8 cm, and the area of 3/4 of this circle is () square cm.

(6) Rectangles, squares and circles with equal perimeters, () has the largest area.

(7) The radius of the circle is increased from 6 cm to 9 cm, and the area of the circle is increased by () square cm.

(8) Cut out the largest circle on the square cardboard with the side length of 10 cm, and the remaining area is ().

(9) Set a wire hoop on the outside of the cylindrical barrel with the bottom radius of 12cm, and the joint part is 8cm, which requires a wire () cm.

(10) Draw a circle with a compass. If the distance between the two feet of the compass is 7 cm, then the circumference of the circle drawn is () cm. The area of this circle is () square centimeters.

(1 1) has two circles, the diameter of the big circle is four times the radius of the small circle, the ratio of the circumference of the small circle to the big circle is (), and the ratio of the area of the small circle to the big circle is ().

(12) The radius of the semicircle is r and the circumference is ().

Second, the application problem.

(1) There is a sheep tied to a stake in the grass. The length of this rope is 4 meters. How many square meters of grass can this sheep eat at most?

(2) After the grenade explodes, the radius of effective killing range is 8m, and the effective killing area is how many square meters?

(3) The aluminum basin is made of a circular aluminum plate with a diameter of 30 cm. How many square meters of aluminum plate does it take to make 1000 such pots?

(4) A rectangular piece of paper, 30 cm long and 20 cm wide, on which the largest circle is cut. How many square centimeters of paper are left?

(5) The circumference of the circular fountain is 62.8 meters, and a cement road with a width of 2 meters is built around this fountain. Find the area of the road surface.

(6) A semicircular fish pond has a diameter of 4m. What is the circumference of this fish pond? How many square meters does it cover?

(7) Around a flower bed with a center diameter of16m, there is a path with a width of 2m. What is the area of this path?

(8) What is the area of an annular iron sheet with an inner diameter of 14cm and an outer diameter of 18cm?

(9) Make a circle with the length of 16 decimeter, and the joint length is 0.3 decimeter. What is the area of this circle?

Fill in the blanks. (20 points)

(1) A book has 200 pages. After reading 35 pages, the ratio of read and unread is ().

(2) The ratio of 2 tons: 750 kilograms to the simplest integer is (), and the ratio is ().

(3) There are 50 students in one class, and 2 people are sick. The ratio of absenteeism to attendance is ().

(4) A project takes 6 days to complete, 10 days to complete. The ratio of working hours used by Party A and Party B is (), and the ratio of working efficiency of Party A and Party B is ().

(5) The degree ratio of the three internal angles of a triangle is 1: 1: 2, and this triangle is a triangle.

(6) The ratio of numbers A, B and C is 5: 4: 3. If the average of numbers B and C is 56, then the number A is ().

(7) a potion. The ratio of liquid medicine to water is 1: 200. There are 75 grams of liquid medicine now, so we need to add () grams of water.

(8) The ratio of boys to girls is 4: 5, and the number of boys is less than that of girls ()%.

(9) When reading, 49% of the students have never read, and the ratio between those who have never read and those who have read is ().

( 10)( )÷8=0.25=4( ) =20:( )。

Second, judge. Mark "√" in the brackets after the question, and mark "×" if it is wrong (10).

(1) The side length ratio of two squares is 1: 3, and its lateral area ratio is also 1: 3. ( )

(2) Team A and Team B each build a section of road, with Team A completing it in 10 and Team B completing it in 8 days. The working time ratio between Team A and Team B is 10:8, and the working efficiency ratio is also 10:8. ( )

(3) The ratio of A number to B number is 7: 4, and A number is 34% more than B number. ( )

(4) Sawing a piece of wood into 10 segments, and each segment is 10% of the whole wood sawing time. ( )

(5) The ratio of the perimeter to the side length of a square is 4: 1. ( )

Third, choose. Fill the letters representing the correct answers in brackets (10).

(1) A number is 50% less than B number, and the ratio of A number to B number is ().

A.2:5 B.5:3 C. 1:2 D.3:5

(2) Take out 20% oil from barrel A and pour it into barrel B. At this time, the weight of the two barrels of oil is equal. The original weight ratio of oil in barrel A and barrel B is ()

Answer 6:5 and answer 5:3

C.4:5 D.7:5

(3) Divide 150 into three parts: A, B and C, where A is 30 and the ratio of B to C is 3: 5, then C is ().

A.75 B.35 C.45

(4) In brine, salt accounts for 10% of brine, and the ratio of salt to water is ().

1: 10 b . 1:9 c . 9: 10d . 10:9

(5) The ratio of the sides of two cubes is 3: 5, and the ratio of their volumes is ()

A: 125

Fourth, simplify the following ratios. (12)

(1)56: 1524 (2)30 minutes: 1.5 hours

(3) 15t: 400kg (4) 0.875: 74

5. Find the ratio of the following ratios. (12)

(1) 9.6: 315 (2) 360kg: 0.45t.

(3)25 cm: 12 m (4)45 minutes: 23 hours

6. Answer the following questions. (36 points)

(1) The volume ratio of oxygen and nitrogen in the air is 21:78,660 cubic meters. How many cubic meters of oxygen and nitrogen are there in the air?

(2) According to the ratio of 2: 3: 4, the school distributed 360 seedlings to students in grades 4, 5 and 6 for planting. How many trees are there in each grade?

(3) The weight ratio of three bags of grain A, B and C is 3: 4: 5. It is known that A, B and C weigh 700g. What is the weight of package C?

(4) The sum of the edges of a cuboid is 96 cm, and the ratio of length to width to height is 5: 4: 3. How big is it?

(5) The efficiency ratio of mentoring to processing a part is 5: 3. We start work at the same time in the morning and process 480 pieces in one day. How many pieces does the master process more than the apprentice?

(6) The school library purchased 294 extra-curricular books and decided to lend them to three classes in grade six, with 45 students in class one, 50 students in class two and 52 students in class three. How many books will each class borrow if it is allocated according to the number of students?

Reference answers and grading standards

1.***20 points, 2 points for each small question.

(1) 3: 2 (2) 8: 3 83 (3)1:24 (4) 3: 55: 3 (5) isosceles right triangle

(6)80 (7) 15000 (8)20% (9)9:4 ( 10)2 16 80

Second, *** 10, 2 points for each small question.

( 1)× (2)× (3)√ (4)× (5)√

Iii. * * *10, 2 points for each small question.

( 1)C (2)B (3)A (4)B (5)A

Four, * * * * 12 points, 3 points for each small question.

( 1)4:3 (2) 1:3 (3) 1:2 (4) 1:2

Five, * * * * 12 points, 3 points for each small question.

(1)3 (2)45 (or 0.8) (3) 12 (or 0.5) (4)98 or 1 18.