There are books in the book corner, such as "Monkey King makes trouble in heaven", "brain twists" and "China Youth Daily"

There are books in the book corner, such as "Monkey King makes trouble in heaven", "brain twists" and "China Youth Daily"

There are books and newspapers in the book corner, such as Monkey King's havoc in heaven, brain twist and China Youth Daily

From 1.2.3.2004.2005, we can take at most several numbers, so that the difference between each two numbers is not equal to 4?

In every 8 consecutive natural numbers, at least four numbers can be taken, and the difference between each two numbers is not equal to 4. Divide every 8 numbers in 2005 into a group, and the last 5 numbers into a group, namely 1,2,3,4,5,6,7,8; 9,10,11,12,13,14,15,16 19931994199519961997199819992000; 20012002, 200320042005 Therefore, it can be divided into 251 groups, and each group takes the first four numbers. Obviously, these numbers meet the requirements. In this way, the total number taken out is 251 × 4 = 1004

The two cars meet four hours after driving from two places with a distance of 600 kilometers. It's seven eighths of the speed. How many kilometers do they travel

Suppose B's speed is x km / h, then a's speed is 7x / 8 (km / h)
4x+4×7x/8=600
32x+28x=600×8
60x=4800
x=80
That is, if B's speed is 80 km / h, then a's speed is 80 × 7 / 8 = 70 (km / h)
4 × 70 = 280 (km)
Car B: 4 × 80 = 320 (km)

As shown in the figure, point F is the midpoint of CD, and AF ⊥ CD, BC = ed, ∠ BCD = EDC. (1) verification: ab = AE; (2) connecting be, please point out the relationship between be and AF, be and CD. (just write the conclusion, do not need to prove)

(1) It is proved that: connecting AC and ad, ∵ point F is the middle point of CD, and AF ⊥ CD, ≌ △ ABC ≌ △ AED. ∥ AB = AE. (2) AF ⊥ be; be ∥ CD

Car a and car B leave from ab 55 kilometers away at the same time. After driving 23 kilometers, car a meets with car B. after meeting, the two cars continue to move forward,
Q: (1) how many kilometers is the second meeting point from B? (2) how many kilometers is the sixth meeting point from a?

For the first time, car a drove 23 kilometers, and car B drove 55-23 = 32 kilometers
For the second time, a drove 23 * 3 = 69 km
So the distance from B is 69-55 = 14 km
In the sixth meeting, Party A and Party B walked 2 * (6-1) + 1 = 11 AB distance, then Party A walked 23 * 11 = 253km
253 / 55 = more than 4 km
That is, a walked two times, more than 33 kilometers
So the sixth meeting point is 33 kilometers away from a

When a = - 3, what is the value of a-2a + 3a-4a + '+ 99a-100a?
When a = - 3, what is the value of a-2a + 3a-4a + 99a-100a?

Why are the math problems here The solution is as follows: first of all, regardless of a 1-2 + 3-4 + +99-100=（1+3+5+…… +99）-（0+2+4+6+…… 1 + 99 = 100 3 + 97 = 100 0 + 100 = 100 2 + 98 = 100 and so on. The above result is - 50A

1. The roads and railways between a and B are parallel. Trains travel 60 kilometers per hour and cars 40 kilometers per hour,
The train from a to B takes two hours less than the car. How many kilometers is the distance between a and B?
2. The number of male workers in a textile factory is 1 / 3 of that of female workers. It is known that there are 380 fewer male workers than female workers. How many workers are there in the factory?

1. If it takes x hours for train from place a to place B, it takes x + 2 hours for car
The equation 60x = 40 * (x + 2) gives x = 4 hours
Therefore, the distance between a and B is 60 * 4 = 240 km
2. There are x male workers and 3x female workers
The equation 3x-x = 380 gives x = 190 people
There are 760 employees in the whole plant

In a monomial formula, the exponent of all letters and the number of times called a monomial formula are only related to what?

In a monomial, the exponent of all letters and the number of times of a monomial are only related to letters

The engineering team completed a section of 8 km road in 7 days. (1) how many parts of the road are built every day on average. (2) how many parts of the road are built in 3 days?
(1) Aunt Wang sold a basket of eggs. She sold 36 eggs on the first day, and half of them on the second day. Now there are 30 eggs left. How many eggs are there in this basket? (2) divide a score, use 2 twice, use 3 once, and get 5 out of 6. What's the score? (3) how many thousands of meters of roads are built every day?

One seventh
Three out of seven
1）96
2) 72 out of 60
3) 8 out of 7

In the acute angle △ ABC, the vertical bisectors of edges AB and AC intersect at point O, and the value of ∠ BOC is calculated

As shown in the figure, the vertical bisectors of ∵ side AB and AC intersect at the point O. the point O is the center of the inscribed circle of the acute angle △ ABC, and ∵ BOC = 2 ∵ a = 2 × 52 ° = 104 °, that is ∵ BOC = 104 °