50 interesting math problems

1. How many New Year cards are there?

There are seven high New Year cards, and after he gave Xing Xing two New Year cards, they had the same number of New Year cards. How many New Year cards are there in Xing Xing?

2. Audio tape

Uncle has 14 tape. After he gave Song Jie/kloc-0 tapes, they had the same number of tapes. How many tapes are there in Song Jie?

3. Who has more books

Xiao Ming and Xiao Qiang have as many books. Later, Xiao Ming gave Xiao Qiang 12 books. Who has more books, Xiao Ming or Xiao Qiang? How many copies are left?

4. How many words did you write?

Ke Qin wrote two pens on the first day, and then wrote 1 pen more every day than the day before. How many strokes has he written in the past four days?

Divide oranges

Dad gives oranges to everyone in the family 1 and the rest 1. If everyone is divided into two, there will be two less. How many people are there in the family? How many oranges did dad buy?

6. Chicken, duck and goose

Mother bought a chicken, a duck and a goose, weighing 12kg. Xiao Ming asked his mother how much a duck weighed. Her mother said: If you know that a chicken and a duck weigh 7 kilograms; A goose and a duck weigh 9 kilograms. Can you figure out how many kilograms a duck has?

7. Weighing bracelet

Among the nine bracelets of the same specification, there is a heavier fake bracelet. On a balance without weight, you are only allowed to weigh it twice at most. Can you find the fake bracelet?

8.* * * How many people are there

Xianxian has many family members, including grandparents, uncles, parents, aunts and uncles. In the second generation, every family has a son and a daughter; In the third generation, men got married and had a son; The third generation, girls are unmarried. Can you figure out how many people are there in Xianxian's family?

9. Penguin treat

There are six wooden chairs in mother penguin's house. One day, six penguins were invited as guests. Every penguin sits in a chair. Strangely, some penguins jumped off the chair as soon as they jumped on it. Everyone looked at the chairs inexplicably, only to find that several existing chairs were broken, with only three legs, and there were six chairs with only 20 legs. Do you know how many broken chairs there are?

10. Feeding time

Teacher Zhang feeds her children six times a day. The first time was 6 o'clock in the morning and the last time was 9 o'clock in the evening. If the interval of breast-feeding is the same, when will Teacher Zhang breast-feed the child?

1 1. Pandas plant trees

Papa panda took little panda and planted a row of trees in front of his house. The spacing between trees is 2m, and there are 10 trees. After planting the trees, Papa Panda asked Panda, How far is it from the first tree to the last tree?

The red panda replied: one is * * * 20 meters long.

Did panda get it right? Why?

12. How many children?

A family photo, a row of six adults, there is a child among every two adults. So how many children are there?

13. police tactical unit and Red Hat

In the swimming pool, all the boys wear blue swimming caps and all the girls wear red swimming caps.

14. How many men and women?

The students in the art group are drawing. One of the female students asked the teacher when school was over. The teacher asked the girl, "Are there more boys or girls in the classroom?" The girl replied that there are equal numbers of boys and girls in the classroom now. After the girl returned to the classroom, a boy asked the teacher when school would be over. The teacher asked the boy, "Are there more boys or girls in the classroom?" The boy replied, "Now the number of boys in the classroom is half that of girls." . Think about it, how many people are here today? How many men and women?

15. Buy buttons

Mom made a jacket for Phoebe, which is 50 cm long. Sew a button every 10 cm. How many buttons should Phoebe buy?

16. Several collocations

Xiaodong has two hats, one is red and the other is white. She has two scarves, a purple one and a black one. Think about it, how many ways can the colors of her hat and scarf match?

17. Monkeys saw wood strips

Mother monkey brought a long piece of wood and wanted to saw it into four sections. Mother monkey asked the little monkey, if it takes 2 minutes to saw a place, how long will it take to finish sawing this piece of wood? The little monkey answered without thinking: it takes 8 minutes.

Is this the right answer? Why?

18. How many boxes are there?

The magician has a big box. The big box contains three middle boxes, and each middle box contains three small boxes. How many boxes does the magician have?

19. "Heavy smoker"

A "heavy smoker" smokes a cigarette every hour, and when he has no money, he connects four cigarette butts to make a cigarette. One day he collected 16 cigarette butts, enough for him to use for several hours.

20. A few minutes

It takes one minute to stick two pieces of paper together, and how many minutes does it take to stick the same six pieces of paper together into a big piece of paper?

2 1 .6 nickels

Xiaokang went to the store to buy a notebook. No, it is worth 24 cents. He only brought six nickels, and there were only two nickels left in the shop, and none of them were 1. Please help Xiaokang find a way to use six nickels and the existing change in the store to change it quickly.

22. Ring the doorbell

It takes 30 seconds for the clock to strike six. If you call 12, how many seconds does it take?

23. Little black bear climbs trees

The little black bear will climb to the top of the tree 8 meters above the ground. The little black bear can only climb 2 meters at a time and slide down 1 meter. Please count how many times it climbed to the top of the tree?

24. How many meters apart?

There are ***40 students in a school participating in the group gymnastics performance, with 4 rows and an interval of 1 meter. What is the distance between the first row and the last row?

25. How many trees have been planted

There is a square garden with five willows planted on both sides. How many willows can you plant in all directions?

26. skillfully place logs

There is a pile of logs in the forest farm, arranged according to the shape of the picture. Each floor below has one more log than the one above. There are 10 logs in the bottom layer and 10 in the * * layer. Ask a * * * how many logs to put, how to calculate easily?

27. Take the apple

There are four apples in Ningning's mother's purse, two of which are ruby apples and the other two are Guoguang apples. Ningning wants to take a ruby apple out of her purse. He must take out at least a few apples at a time, so that there must be a ruby apple among them.

28. Playing poker

There are two hearts and two spades, lying face down.

(1) If you draw a card at random, what card might it be?

(2) If you draw two playing cards, what cards might these two cards be?

(3) If you draw three playing cards, what cards might these three cards be?

29. Divide the roses

There are 13 roses. How many ways can you divide them into two piles? Please write the division formula.

30. Sum and product

The numbers whose sum of two integers is 13 are 0 and 13, 1 and12,2 and1,3 and 10 ... which two integers have the largest product?

3 1. Triangular plate and square plate

(1) Jiajia has seven triangular and square plates. How many triangular plates may there be? How many square plates may there be?

(2) Yaya has five triangular plates, which are distributed in Heping and Hai. How to distribute it?

(3) Yaya has four square boards: Pingping, Haihai and Jingjing. How to distribute it?

32. How many people

Six people from a * * * class took part in the competition. There are 4 people in the math contest and 3 people in the chemistry contest. How many people take part in the math and chemistry competitions at the same time?

33. Buy pins

Heihei took four coins and went to the store to buy pins. The unit price of pin is 1, 2,3 3... 10/0. He can buy any pin without the help of a salesman. Do you know which coins are on the black belt?

34.* * * How many?

There are three stamps with the same number: one penny, two cents, four cents ***35 cents. How many three kinds of stamps are there?

35. Same color ball

There are 10 white balls and 30 red balls in the bag. How many balls do you have to take out to ensure that you can take out two balls of the same color at a time?

36. Number of students

The number of students in Class One, Grade Two is between 50 and 55. In class, two people share a bench, but one sits alone. When playing games after class, every five people are divided into groups, but there are six people in a group and there are more than 50 people in this class?

37. What does it matter?

A is B's brother, C is Ding's brother, Ding is A's father, and C is B's?

38. One day and one night

A day and a night (24 hours) passed, which was three times the rest time. What time is it now?

39. how many times have you met

When the long hand (minute hand) of a clock makes one turn, the short hand (hour hand) can only turn from one number to another. How many times can the long and short hands of a clock meet from 8 am to noon 12?

40. Rearrange the graphics

Please rearrange the figures in the table as required, so that there are no figures with the same shape on the horizontal, vertical and diagonal lines in the chart.

4 1. How much is it?

There are three kinds of ***4 coins (each coin has at least 1 coin), which are 5 cents, 2 cents and 1 coin respectively. How many situations are there? How much is each?

42. How many coins

There are 14 nickels, dimes and dimes, and * * * 26 cents. Please analyze it. How many nickels, dimes and dimes are there?

43. Three kinds of fish

Two generations of love bought hairtail, yellow croaker and flounder. You should know that each hairtail is as heavy as three yellow croaker, and two yellow croaker are as heavy as three flounder. Compare, hairtail, yellow croaker and flounder, which is the heaviest? Which is the lightest?

44. Cut watermelons skillfully

A big watermelon, please cut it three times and cut it into eight pieces. How to cut?

45. cut the cake

One knife can divide the cake into two parts, two knives can divide the cake into four parts and three knives can divide the cake into eight parts. Can you cut four knives and divide the cake into twelve parts?

46. Interesting problem of planting trees

British scientist Newton once had an interesting question about planting trees. He said there were 9 trees, planted in line 10, with 3 trees in each line. Please think about it, how to plant it?

47. Five-person ranking

Five people took part in the competition, and A was not the first one. B is neither the first nor the last; C is the one after a; Ding is not the second; E is two places behind D. Please name the rankings of these five people. (Time limit: within 2 minutes)

48. One day, some children went to a candy store to buy candy. It happens that there is a discount in the store, and they can exchange two pieces of candy paper for one more candy. They thought about it and finally bought five pieces of sugar. When they left, they ate 1 1 candy.

A butcher killed a pig, but the pig ran around and ran to the herd. The butcher was very angry. The butcher said, "I must kill you." Another man said, "There are 1000 pigs here. How can you find them? Are you going to kill all 1000 pigs? " The butcher said, "I put these 1000 pigs in a row, first kill the first one, then kill the third one, then kill the fifth one, after the first round, then kill them in the original formation, and finally there is one left." I don't believe it is still alive! " In this way, all the pigs were dragged to the slaughterhouse for slaughter. The clever pig was among the pigs in the chaos, but it escaped the bad luck and asked where it ranked.

This question was a riddle written by Einstein in the early 20th century. He said that 98% of the people in the world couldn't answer it. Can you answer that?

1。 In a street, there are five houses painted in five colors.

2。 People of different nationalities live in every house.

3。 Everyone drinks different drinks, smokes different brands of cigarettes and keeps different pets.

The question is: Who raises fish?

Hint: 1, English people live in red houses.

2. Swedes have dogs.

3. Danes drink tea.

The green house is on the left of the white house.

5. The owner of the green house drinks coffee.

6. People who smoke pall mall cigarettes keep birds.

7. The owner of the yellow house smokes Dunhill cigarettes.

People who live in the middle house drink milk.