1. first group: 1, 3, 7, 8 second group: 5, 9 third group: 146 question: what are the rules (answer: tone)
2. In twenty-four hours, how many times did the minute hand and the hour hand become vertical? (44 times)
3. Two typists can type two pages in two minutes. How many typists (44 people) do you need to type eighteen nights in six minutes?
A bar of soap will eventually become a small bar of soap. Six small bars of soap can be made into an ordinary soap. 176 how many ordinary soaps can a small soap make? (35 yuan)
5.(987 1+9872+9873+9874+9875+9876+9877+9878+9879)/9=? (Hint: average answer: 9875)
6.X+Y+Z=X*Y*Z，X≠Y≠Z≠0( 1，2，3)
Why is the manhole cover round? I didn't intend to tell you the answer to this question, but I still ... First, the manhole is located on the road, and people come and go every day. Attention should be paid to the safety of pedestrians when designing, and the manhole cover should not fall into the manhole. If it is designed as a triangle or a square, although the cover is larger than the manhole, it may still fall down. And if it is round, because the diameter of the circle is equal, the cover will not fall off as long as it is slightly larger.
Secondly, because the manhole sometimes needs manual combing or threading, the area of the manhole is required to be as large as possible at this time. In these figures, when the perimeters are equal, the area of the circle is the largest. At the same time, the circle conforms to our body shape, which is convenient for staff to go in and out.
Thirdly, the sides of a triangle or square are composed of straight lines, forming an acute angle, which is easy to hurt people if touched during maintenance. And the edge of the circle is an arc, so this problem will not appear.
Fourth, the cover of the sewer is round, which is the requirement of structural stress:
So as to bear loads from uncertain directions. Imagine that if the cover of the sewer is square or other angular shapes, when the impact load of the wheel acts on it, the angular parts are easily damaged. The manhole of the sewer is made into a circle because of the force-the arch structure can effectively resist the earth pressure.
But because the circle has the largest area in the figure with equal circumference, it uses the most materials. Therefore, from the economic point of view, some places have designed and used manhole covers with other shapes. )
8.(A+B)*(A-B)=？ I was going to add your own answer: the square of A-the sum of the squares of B (the square of A B) = the square of A2AB+the square of B.
9.1() 2 () 3 () 4 () 5 () 6 () 7 () 8 () 9 () =100 Fill in the appropriate equal sign in brackets to make the equation hold (this is what I thought of myself, and then give you a simple answer:/kloc-0.
10. A businessman spent 70 yuan to buy a dress of 12 and then sold it. Later, it was found that the 100 yuan paid by the buyer was counterfeit. Ask the businessman how much he has lost (suggestive drawing can simplify the answer to the question: 88)
1 1. Compare the sizes of 333223/333225 and 666335/666337 (666335/666337).
12. Two people start from the same place, walk 4 meters in opposite directions, then turn left and walk 3 meters. How many meters are they apart? It is suggested that the sum of squares of two right-angled sides in a right-angled triangle is equal to the square of the hypotenuse. In this problem, it is the square of 3 plus the square of 4 = the square of 5. Answer: 10.
13 suppose the thickness of a piece of paper is 0. 1. When the paper is torn in half, repeating this process for 25 times will be like () A. A mountain B. A person C. A building D. A book (don't guess that it is 3355.4432m after calculation, so the answer is: A).
14. Judge right or wrong through math reading; Judge right or wrong; Eight plus eight equals fifteen. Eight plus eight equals fifteen (answer: ...)
15. Two straight lines can intersect at most 1 time. What about four straight lines? How about five? I hope you can think for yourself: four is six, and five is 10.
16. How many times do the hour hand and the minute hand * * * coincide in twelve hours (think about eleven o'clock 1 1 time)?
17. A bacterium divides into two four-hour divisions every half hour (answer: 16).
18. There are two candles with different thicknesses. Thick candles burn for 4 hours, and thin candles burn for 6 hours. Now, two candles are lit at the same time. After burning for two hours, the two candles are the same length. What is the original height ratio of two candles? (4:3)
19. Divide a square with a surface area of 48 square decimeters into two identical rectangles. What is the sum of the surface areas of these two cuboids? (64 square meters)
20. It's hard! I admit I can't. Why is 1+ 1 equal to 2?