2 questions are obtained in the third grade of elementary school

This question can be solved with a multiplier relation.

1. Picture books are 2 times that of science and technology books, and if you look at science and technology books as 1 copy, picture books are 2 copies2. There are 20 more story books than picture books, and the 20 more books are subtracted from the total, and let's assume that there are as many story books as picture books.

Therefore, from the above, it can be obtained that the three books can be divided into 5 parts. 2 copies of picture books, 1 copy of science and technology books, and 2 copies of story book hypothesis.

That is: 245-20 = 225 (book) 225 5 = 45 (book) picture book: 45 times 2 to get 90, 90 picture books, 45 science and technology books, story book 90 + 20 = 110 (book).

Set the science book to x:

Picture book = 2x;

Storybook = 2x+20;

So it is: 2x+x+2x+20=245

5x=245-20

5x=225

x=225/5

x=45 so there are 45 science books, 90 picture books, and 110 story books.

I don't know if you've taught equations.

Science books, picture books, and storybooks are ABC respectively

a+b+c=245

b=2ac-b=20

The most basic ternary equation. The solution is: a=45, b=90, c=110.

Analysis: From 245 to 20 books, the number of storybooks and pictures is equal, which is twice as many as science and technology books. In other words, the sum of storybooks and picture books is 4 times that of science books. Then 245-20 is 5 times as much as a science book.

So the column: (245-20) (2+2+1)=225 5=45 (Ben).

45x2=90 (book).

90 + 20 = 110 (Ben).

A: There are 45 science and technology books, 90 picture books, and 110 story books.

First of all, it is the change in learning, the knowledge learned before the third grade is some relatively simple knowledge, many times students can solve it by rote memorization, however, the third grade is a transition period, learning will add a lot of thinking and methods, at this time students will have an adaptation period, if the child adapts to the grades can go up quickly, can not adapt to the grades will decline, so, at this time parents should communicate more with the child, and help the child to solve some problems and doubts, In this way, children can lay a good foundation from an early age, which is more conducive to future learning.

Secondly, it is the psychological change of students, children are relatively praised and encouraged by parents when they are young, but in the third grade, children gradually grow up, parents begin to pay attention to their children's grades, at this time children will often be criticized when they make mistakes, and at the same time receive less praise and encouragement, at this time it will have a great impact on the child's psychology, and even leave a shadow, so, as a parent, we must pay attention to this, praise and encouragement in the process of children's growth is indispensable, It is not possible to leave a psychological shadow on the child, which will ruin a child after a long time.

Finally, it is the increase in the curriculum, which will make the child feel the pressure, and when the English course is added in the third grade, there is no doubt that the child's learning will become more intense, because it is easier in the first and second grades, and suddenly the nervous child will not be able to adapt, which may affect the child's grades, be sure to lay a good foundation.

Therefore, at this moment, parents must give their children a good check, so that they can better continue their next studies.

The distance that the eagle flies in 40 seconds: 40 40 = 1600 metersThe distance that the swift flies in 40 seconds: 33 40 = 1320 metersThe distance that the eagle flies more than the swift: 1600 1320 = 280 metersThe difference between the eagle and the swift is 300 meters.

So 40 seconds the eagle can't catch up with the swift.

The eagle and the swift are 300m apart, the eagle flies 7m more than the swift per second, and after another 40 seconds, it flies 280m more than the swift, 280 is less than 300, and the swift cannot catch up.

This is a series of equal differences!

Prime Minister + last item) * Number of items 2

Top me!!

It is equivalent to transporting grain out of 6 granaries, so it turns out that each granary has 3*8 6=4 tons.

It turns out that each granary has x tons of grain.

8（x-3）=2xx=4

Suppose there were x tons of grain.

8（x-3）=2x

So 8x-2x=24

6x=24x=4

3 8 = 24 (tons).

24 (8-2) = 4 (tons).

Explanation: Remaining grain = total amount of 2 granaries.

Then the grain shipped out is equivalent to the total amount of 6 granaries.

You can rest for a total of 3 days at the same time. They are No. 1, No. 13, and No. 25.

The greatest common multiple of 4 3 2 is 12

31 12 = 2 surplus 7

There are 3 days in total.

1+2+3=6 30 6=5 In September, the whole family will have 5 days off at the same time.

200-10 = 190 pcs.

50x2=100pcs.

190-100) 30=3 people.

2 adults, 3 children.

The meaning of sharp sharp is: fast or pointed [refers to the sharp edge of a knife and gun], as opposed to "blunt".

Sharp means sharp and sharp.

Rui here means sharp.

Rui can mean sharp, sensitive, courageous momentum, sophisticated, sudden, etc., here refers to sharpness.

Sharp means sharp, sharp and fast (such as a blade, etc.). It is also a metaphor for sharp and sharp eyes, words, etc.

The meaning of the sharp word "sharp":

sharp ruì1] sharp, pointed, as opposed to "blunt": sharp. Unstoppable. (This is the original meaning.) [2] Sensitive Sense: Acute.

3] Courageous momentum: forge ahead. Recharge your batteries.

4] Excellent: Elite.

5] Sudden, abrupt: sharply decreased, sharply increased.

It is the opposite of bluntness, which refers to the sharpness of the blade, and also refers to the sharpness and clarity of the gaze and speech, implying that the writing is very good.

Sharp is the meaning of sharp, sharp is the opposite of blunt here, sharp also has the meaning of courage and sensitivity. Words like elite, keen, etc.

The sharp word "sharp" here should mean sharp, sharp.

Sharp means sharp and sharp. Sharp.

Sharp sharp, means sharp, sharp, and so on.

Is this question you asking a sharp sharp explanation? Rui should mean sharp, right?

Sharp sharp, its interpretation means "sharp sharp", I hope it can help you.

Sharp: It is mostly used to describe sharp and sharp utensils, and it can also describe people's keen eyes and insight. Sharp solution is sharp, sharp.

Rui means that it is a very sharp instrument, and it is a very sharp feeling.