Example 2: Xiao Li likes collecting stamps. He bought two kinds of stamps with 10 yuan, namely 15 stamps. So how many 6-cent stamps did he buy? How many eight-cent stamps are there?
Example 3: There are 100 students in Xuanwu Lake Primary School, with an average score of 63, including 60 for boys and 70 for girls. How many more boys than girls?
Example 4: The school held a math contest with 20 questions. Answer a question correctly and get 5 points; If you don't do a question or do a wrong question, deduct 3 points; If Liu Hao got 60 points, how many questions did he answer correctly?
Example 5: There are three kinds of coins with face value of 1, 2,5, in which 1 is 1 1 times the number of 2. It is known that the total face value of this pile of coins is 1 yuan. How many nickels are there?
Exercise: 1 There are several chickens and rabbits in the same cage. There are 40 heads from the cage and 130 feet from the bottom of the cage. How many rabbits and chickens are there in this cage?
Spider has eight legs, dragonfly has six legs and two pairs of wings, cicada has six legs and a set of wings. Now there are three bugs ***2 1, 140 legs and 24 pairs of wings. How many bugs are there per bug?
There are 40 chickens and rabbits. A chicken has 70 fewer feet than a rabbit. How many chickens and rabbits are there?
4. The school bought two kinds of pencils, each with 40 cents and 80 cents, which cost 68 yuan. It is known that there are 40 pencils with 80 marks more than those with 40 marks, so how many did you buy?
In a parking lot, there are exactly 24 parked vehicles (cars and three-wheeled motorcycles), in which each car has four wheels and each motorcycle has three wheels. These cars have 86 wheels. So, how many tricycles are there? 6. A factory has 27 masters with 40 apprentices, and each master can bring one apprentice, two apprentices and three apprentices. If there are twice as many masters with one apprentice as other masters, how many masters with two apprentices?
7. A school with 80 students has 12 dormitories. There are three dormitory sizes: large room with 8 people, medium room with 7 people and small room with 5 people. Among them, medium-sized rooms have the most dormitories. How many rooms are there in the middle room?
8. Today, there are 35 chickens and rabbits and 94 feet. How many chickens and rabbits are there?
9. There are a group of ostriches and giraffes in the zoo. They have 30 eyes and 44 legs. How many ostriches and giraffes are there? 10, three insects * * * have 18, they * * * have 20 pairs of wings and 1 16 legs, among which each spider has 8 legs without wings; Every dragonfly has two wings and six legs; Every cicada has a pair of wings and six legs. How many are these three kinds of insects?
1 1, 30 Chinese books and 24 math books, 83.40 yuan, each Chinese book is 0.44 yuan more expensive than each math book. What is the price of each Chinese book and each math book?
12, the female squirrel picks pine nuts, and can pick 16 every day in sunny days and 1 1 in rainy days. There are sunny days and rainy days, among which sunny days are 3 more than rainy days, but the number of picks is 27 less than sunny days. How many days did you choose?
13, a math exam * * * 20 questions, 5 points for one question, 1 point for one question, no score, and 76 points for Xiaohua. How many questions did Xiaohua answer correctly?
14, and the distance between Party A and Party B is 12km. Xiao Zhang went from Party A to Party B, stayed in Party B for half an hour, then returned to Party A from Party B, and Xiao Wang went from Party B to Party A, stayed in Party A for 40 minutes, and then clustered back to Party B.. It is known that the two started from Party A and Party B at the same time. Four hours later, they met on their way back. If Xiao Zhang is faster than Xiao Wang 1. 5 kilometers. Find the speed of two people.
15, there is a truck carrying 2000 glass bottles, and the freight is calculated according to the number of intact bottles when they arrive, and each bottle is 20 cents. If there is any damage, the broken bottle will not be compensated for the freight, but one yuan per bottle, and the freight is 379. 6 yuan, how many glass bottles were broken during handling?
16, a project, Party A 12 days, Party B 18 days, now Party A has worked for a few days, and Party B continues to work on the rest, which has been used for 16 days. How many days did Party A do it first?
17, I bought 20 copies of Synchronous Exercises of Mathematics for Grade Five and Synchronous Exercises of Mathematics for Grade Six in five days, including one copy of Synchronous Exercises of Mathematics for Grade Six in 5 yuan and one copy of Synchronous Exercises of Mathematics for Five Years in FFKJ.Net from Feifei Courseware at 3.75 yuan. Statistics show that "synchronous math exercises for grade six" sold in these five days are more than "synchronous math exercises for grade five" 162.5 yuan. How many copies of these two books were sold by the bookstore in these five days?
18. There are two kinds of glass balls in the box, red ones are three times more than white ones. Take seven white balls and 15 red balls out of the box at a time. If you take the ball several times, there are 3 white balls and 53 red balls in the box. How many red balls are there in the box? 19, beat a and b. If it hits, A gets 4 points and B gets 5 points; If you miss, B will lose 2 points and 3 points, each person will shoot 10, and * * * will hit 14. If the score is fixed, A will get 10. How many rounds will A and B get?
20. Two students, Jiao Jiao and Tian Tian, held a math contest. If they answer a question correctly, they get 20 points; if they answer a question incorrectly, they get 12 points. They scored 208 points, and Jiao Jiao scored 64 points more than every day. Ask them how many questions they answered correctly.
2 1. An exam has been opened 24 times, with 426 questions, and the number of questions each time is 25, or 16, or 20. So, how many times have you answered 25 questions?
22. There is a folk song, "A team of hunters and a team of dogs walk side by side, with 360 heads and 390 legs." How many hunters and dogs are there? (required)
23. How many stamps with 4 cents, 8 cents and 10 can I buy for one yuan *** 15, and how many stamps with 1 0 can I buy at most?
24. Three students from a primary school went to take part in a math contest. * * 10 questions, if you answer one question correctly, you will get 10 points, if you answer one question incorrectly, you will be deducted 3 points, and if you don't do it, you will get 0 points. They all did all the questions, an 87, a 74 and a 9. How many questions did they answer correctly? 25. A class went out for a spring outing, bought 99 tickets, and spent * * * on 280 yuan, including a one-way ticket to 2 yuan and a round-trip ticket to 4 yuan. What's the difference between a one-way ticket and a round-trip ticket?
The answer is not easy. I hope it helps you. Please accept those that can be answered (* _ _ *)