First, the issue of normalization.
Two cars (1 and 2) need 240 liters of gasoline to drive 300 kilometers. According to this calculation, how many liters of gasoline do five cars need to transport goods to places 800 kilometers apart at the same time?
2. Five tractors plowed 12000 mu of land in 24 days. /kloc-how many tractors do you need to plow 54000 mu in 0/8 days?
Second, the average problem.
1. In a math exam, the average score of Chinese and English subjects is 96, and the average score of Chinese and math subjects is 92. What's the score in each subject?
2. The sum of seven consecutive even numbers is 1988. What is the largest number of these seven consecutive even numbers? .
Third, the problem of doubling.
1, rectangular, 30 cm in circumference, twice as long and wide. Find the area of this rectangle.
2. The sum of three adjacent numbers in a vertical line on the calendar is 30. What's the smallest number?
Fourth, the problem of different times.
1. The number of teachers in the two schools is equal. Because of work needs, 30 teachers were transferred from school A to school B. At this time, the number of teachers in school B is exactly three times that of school A. How many teachers are there in both schools?
2.A and B, if A plus 320 equals B, if B plus 460 equals 3 times A, what are these two numbers?
Verb (abbreviation of verb) and difference problem
1, two barrels of oil * * * weigh 30kg. If 6 kilograms of oil in barrel A is poured into barrel B, the weight of the two barrels of oil is the same. How much oil do they have?
2.500 kilograms of alloy is made of tin and aluminum. The weight of aluminum is heavier than that of tin 100 kg. How many kilograms are tin and aluminum respectively?
Sixth, the issue of age.
1, the mother and daughter are 64 years old, and the daughter is three years and eight years older than her mother. How old are the mother and daughter?
2. Grandpa is 72 years old and grandson 12 years old. A few years later, grandpa was five times as old as his grandson. A few years ago, my grandfather was 13 times older than my grandson.
The chicken and the rabbit are in the same cage.
1 .49 chickens and rabbits, 100 feet, how many chickens and rabbits?
2. One hundred monks are divided into one hundred steamed buns, three big monks and three little monks. How many monks are there?
3, a math contest ***25 questions, it is stipulated that 1 questions will be given 6 points, and 1 questions will be deducted 4 points if they are wrong (or can't do it). Zhang Lin got 80 points in the exam. How many questions did he answer correctly?
Eight, profit and loss problem
1. Auntie eats cookies for kindergarten children. If you give each child 3 cookies, you will add 16 cookies. If everyone is divided into five pieces, then there are four cookies missing. How many children and cookies are there?
2. Young Pioneers participate in greening and planting trees. They plan to plant twice as many apple seedlings as pear seedlings. If everyone plants three pear seedlings, there are still two left. If everyone plants seven apple saplings, there will be six fewer. How many young pioneers are there? How many apple and pear trees are they going to plant?
The school made a general cleaning and assigned several people to clean the glass. Two of them were cleaned with 4 pieces each, and the rest were cleaned with 5 pieces each, leaving 12 pieces; If everyone wipes 6 pieces, it's just finished. How many people clean the glass and how many pieces of glass are there?
Nine, clever perimeter
1. For a rectangular cardboard with a length of 5 decimeters and a width of 4 decimeters, cut a square with a side length of 1 decimeter from each of the four corners. What is the circumference of the rest?
The square is divided into five rectangles, and the circumference of each rectangle is 30 cm. What is the circumference of this square in centimeters (Figure 13-6)?
X. Travel issues:
1. If you drive 60 kilometers per hour from A to B, you will be 4 hours late; If you drive at a speed of 96 kilometers per hour, you will arrive 2 hours earlier. How many kilometers per hour should you drive in order to arrive on time?
Xiao Wang walks to work and gets off work by bus. It takes 90 minutes to go back and forth. If he goes to work by bus, it will take him 30 minutes to go back and forth. If he walks to work, how many hours will it take him to go back and forth?
Someone runs 5 kilometers per hour. If it takes 8 minutes less to ride a bike than to run, how many times can he ride a bike faster than to run?
XI。 Centralized question:
1. There is a 30% alcohol solution of100g. How much water is added to dilute it into 24% alcohol solution?
2. There are 600g of saline water with a concentration of 7%. How many grams of salt does it take to increase the brine concentration to 10%?
Navigation of ideas: solvent rearrangement remains unchanged.
3. The salt content of seawater is 5%. How many kilograms of fresh water should be added to 40 kilograms of seawater to make the salt content of seawater reach 2%?
XII. Percentage problem:
1, A is more than B 10%, and B is less than A by what percentage?
2. Deposit 5000 yuan, with annual interest rate of 2.5% and interest tax of 5%. How much can I withdraw with interest and principal after two years?
3. The length, width and height of the cuboid block are 5cm, 4cm and 3cm respectively. If it is sawed into the largest cube, how much smaller will it be?
Thirteen. Ratio and proportion:
1. The bottom area ratio of two rectangular containers A and B is 2: 3, and the height ratio is 2: 5. How much water can these two rectangular containers hold?
2. It takes 65,438+0/2 hours for Master Zhang to produce a part and 65,438+0/3 hours to produce a part. What is the work efficiency ratio between Master Zhang and others?
Fourteen, engineering problems:
1, one project 10. One team will finish it alone in 0 days, and one team will finish it alone in 30 days. Now the two teams work together. During this period, Party A has two days' rest and Party B has eight days' rest (there is no case that two teams have a rest at the same time). How many days does it take from start to finish?
2, 14. A slender candle is lit in 4 hours, and a short candle is lit in 6 hours. After two candles are lit at the same time for 2 hours, the remaining length is exactly the same. It turns out that the stubby candle is a fraction of the long thin candle.
3. Party A 16 days, and Party B 12 days can complete a project ... Now B does three days, and A does the rest. How many days will it take to complete this project?
Fifthly, the question of the meeting.
1, an express train and a local train leave from Station A and bilibili at the same time in opposite directions. After the 6-hour rendezvous, the express train will continue to travel for 3 hours and then arrive in bilibili ... It is understood that the local train travels 45 kilometers per hour. How many kilometers are the two stops apart?
12, car A and car B leave from A and B respectively at the same time. After five hours of meeting, they moved on. Three hours later, car A arrives at car B, and the distance between car B and car A is still120km ... What are the speeds of car A and car B respectively?
6. Party A and Party B walk in opposite directions from Party A and Party B at the same time. When they meet, the distance is a 120 meters. After meeting, they will continue to move forward and return immediately after reaching their destination. They meet again at a distance of a 150 meters. What is the distance between AB and B?
7. The distance between A and B is 38 kilometers. At the same time, Party A and Party B set out from two places and headed for each other. Party A travels 8km per hour, and Party B travels 1 1 km per hour. A returns to A immediately after arriving at A, and B returns to B immediately after arriving at A. How many hours later did they meet on the way? How far is it from A when we meet?
Third, the train problem.
1. A team is 450 meters long and advances at a speed of 2 meters per second. How many minutes does it take for a person to walk to the front of the line at a speed of 3 meters per second and then return to the end of the line?
4. It takes 65 seconds for a train to cross a bridge with a speed of 1000m, and 50 seconds to cross a tunnel with a speed of 730m m.. Find out the speed and length of this train.
Fourth, the problem of running water.
1. When the ship is sailing in the river, the downstream speed is12km/h and the upstream speed is 6km/h.. The ship speed is () kilometers per hour, and the water speed is () kilometers per hour.
The distance between Port A and Port B is 360 kilometers. A ship sailed from Port A to Port B 15 hours, and returned to Port A from Port B, sailing against the current for 20 hours. At present, there are motor boats with a speed of 12 km. How many hours does it take to go back and forth between the two ports?
Geometric problem
136. A cylindrical iron drum without a cover is 24 cm high and the bottom radius is 10 cm. How many square centimeters does it take to make this bucket? (Keep the whole hundred square centimeters)
138. A cylindrical grain depot filled with wheat, with a bottom area of 3.5 square meters and a height of 1.8 meters. How many cubic meters is the volume? If these wheat are piled into a conical wheat pile with a height of 1.5 meters, how many square meters will it occupy?