1.++= (Students must learn the rules of this kind of problem)
2, 77 49 36 65 438+08 8 (There are many such problems, so more screening is needed)
2.× = 13× 4 = 52 (fill in the natural number 1-5 in the box to make the equation hold. Do not repeat the filling. )
3. Add three different numbers after 947 to form the smallest six digits that can be divisible by 2, 3 and 5 at the same time. This number is 947 130.
4. Write five prime numbers and arrange them in order from small to large, so that every two adjacent numbers differ by 6. 5、 1 1、 17、23、29
Today is Arbor Day. Xiaoming got seven trees. He wants to plant them in six rows. Please help Xiaoming design this plan. Draw the design in the box on the right.
6. There are two rectangular pieces of paper of the same size, with a length of 1 decimeter and a width of 3 cm. Overlap them vertically and stick them together to form a cross-shaped figure. Its circumference is and its area is.
7. Subtract the last non-zero integer from the decimal point. If you add a decimal point to an integer to make it a decimal point, the difference will increase by 154.44, and the integer will be 156.
8. The greatest common divisor of two natural numbers is 14 and the least common multiple is 560. Their product is 14×5× 14×8=7840.
9. If there are arrays: (1, 1, 1), (2,4,8), (3,9,27), ..., then the sum of the single digits of the three numbers in the 1998 group is 8+4+.
10. There is a poem "How many monks are there in the temple" in Xu Ziyun's "Arithmetic Dacheng": The majestic ancient temple is in the mountains, and I wonder how many monks there are in the room. 364 bowls, the monks have just used up. Three people eat a bowl of rice and four people eat a bowl of soup. Excuse me, sir, how many monks are there in the temple? Poetry: Three monks eat a bowl of rice and four monks drink a bowl of soup, which is exactly 364 bowls. There are 624 monks in the temple.
1 1. The clock is 4 minutes slow every hour. According to this calculation, the standard time is 2 1: 00 when the time is aligned at 6: 00 in the morning and the clock points to 8: 00 in the evening. (in 24-hour format)
12. As shown on the right, four isosceles right triangles form a big square, and the largest circle is drawn in the big triangle. It is known that the area of an isosceles right triangle is 2 square centimeters, so the area of this shaded part is (1. 14) square centimeters. 3. 14×2×2-2×4=4.56 4.56/4= 1. 14
13. Ms. Yang made a real estate speculation and bought 2 suites, but she had to sell them immediately because of lack of money. When each set was sold at a price of 900,000 yuan, she earned 50% on one set and lost 50% on the other. Did she make a profit in the whole business? Still lost? A: I lost 600,000 yuan (earned or lost).
14. A cake can be cut into two pieces, and two knives can be cut into four pieces. Excuse me, 20 knives can cut n× (n+1)/2+1= 211cake at most. Forgot the rule that you can't cut the horizontal knife. This kind of questions should be combined with "how many lines and angles are there between points" to teach students to find and summarize)
15. In a pastoral area, it is stipulated that every time herdsmen pass a pass, half of the sheep will be confiscated and one will be returned. Uncle Wang has been herding sheep for 20 times, and there are only two sheep left. Did Uncle Wang have two sheep at first? Once the problem is reversed, solve it immediately. )
16. Supermarket business is very good. In order to improve the service quality, employees are required to pack sesame oil by the whole kilogram. How many kinds of packaging do you need at least to meet all the requirements of customers under 50 kg (to ensure the minimum number of packaging when purchasing)? Please write down the optimization plan of packaging below.
Answer: * * * 6 kinds of packages: 1 kg, 2 kg, 4 kg, 8 kg, 16 kg, 32 kg.
17. On the one-way railway bridge, people can't go by train, and people can't go by train. Pedestrians should be especially careful when crossing the bridge. Xiaoming is in a hurry to go to school. When he had just reached two-thirds of the bridge, he saw a train with a speed of 60 kilometers per hour coming ahead. He has no time to think about it. With the word "run" as the pledge, he continued to run a third of the bridge. The train just stepped onto the bridge. If Xiaoming runs backwards, the train is crossing the bridge. Xiaoming's running speed should be 20km/h, which is very difficult, but some pupils got it right. )
18. There is a poem that says: Dajiangdong has gone to the waves, and there are many people through the ages; In the 1930s, the governor of Wu Dong died young and at a double-digit rate. Ten is less than one, and one is twice as much as ten; Which student is faster, how many years of life belongs to Zhou Yu. Zhou Yu died at the age of 36.
19. Party A and Party B start from two places, which are100km apart, and go in opposite directions. Party A walks 6 kilometers per hour and Party B walks 4 kilometers per hour. A adopted a little black dog named Jia Jia. Jia Jia, the dog, ran to B at a speed of 15 km per hour. When he met B, he ran back to A; When I met A, I ran back to B. The dog Jiajia didn't stop until A and B met. When Jia Jia the dog won a dog bone, he was very happy. Q: Jia Jia's dog ran away150km. (The dog runs at the same time when Party A meets Party B, so it is100/(6+4) ×15 =150km).
20. Chickens and rabbits are in the same circle, with 250 heads and 700 feet. How many chickens and rabbits are there? Answer: chicken 150, rabbit 100. (This kind of problem is regular: half of the total number of feet-total number of heads = total number of heads of quadrupeds, and there are two feet left. )
2 1. Six people, A, B, C, D, E and Ji, sit around the round table and play chess. It is known that A and B are separated by one person and sit on the right side of B; I sat opposite Wu; C and d are separated by a person, sitting on the right side of d; D and e are not adjacent. Please mark the positions of A, B, C, D, E and B in the picture on the right.
22. The length, width and height of a rectangular pool are three continuous natural numbers, with a volume of 720 cubic centimeters and a surface area of 394 square centimeters. (the smallest height. 8、9、 10)
23. If there are at most five Sundays in a month, then at most (5) months in a year are five Sundays.
24. A project took Party A 30 days and Party B 40 days to complete. Now they are working together for 25 days, during which Party A has twice as many days off as Party B ... Please take five days off?
25. If someone walks 75 meters per minute from A to B, he will be 8 minutes late; If he walks 80 meters per minute, he will be six minutes late. He should walk at a speed of 100 meter per minute to arrive on time. Let the standard time be x (x+8)*75=(x+6)*80, and then divide it by the standard time, and the answer is 100m/min.
26. The volume difference between two cubes is 1200 cubic centimeters. If one side of each cube is taken as the bottom surface and processed into the largest cone, the volume difference between the two cones is 3 14 cubic centimeter.
27. It takes only 20 minutes for Xiao Ming to go to school by bike. One day, I had to walk because there were 2 kilometers of roads being built on the way. Walking speed is one third of that of cycling, so it took 36 minutes to get to school that day. Xiaoming's home is 5 kilometers from school? Let the road be x {2/(x/20) *1/3}+{x-2/(x/20)} = 36, and the answer is 5km.
28. In the final exam of a class, the language pass rate is 90% and the math pass rate is 94%. 4% failed in Chinese and math, and 44 passed in Chinese and math. There are 50 students in this class.
Let the class size be x, x-( 10%x+6%x-4%x)=44, and the answer is 50.
29. Five workers processed 735 parts, and 65,438+035 parts were processed in two days. Known 1 person takes two days off 1 day. At this work efficiency, if no one asks for leave in the next few days, it will take eight days to complete the task.
Assuming that each person produces X, 4x+5x = 135 per day, then X =15 (735-135)/15 * 5 = 8 days.