The basic knowledge of a primary school, for the conversion of circular decimals and fractions, such as how to convert 0.12 (12 cycles) into fractions

The basic knowledge of a primary school, for the conversion of circular decimals and fractions, such as how to convert 0.12 (12 cycles) into fractions

How to convert a circular decimal into a fraction
As we all know, finite decimal is another form of decimal fraction. Therefore, any finite decimal can be directly written as a few tenths, percentages, thousandths Then can an infinite decimal be transformed into a fraction?
First of all, we need to make it clear that infinite decimal can be divided into two categories according to whether the decimal part is recycled or not: infinite recycled decimal and infinite non recycled decimal. Infinite non recycled decimal can not be converted into fractions, which will be explained in detail in middle school. Infinite recycled decimal can be converted into fractions. So, how does infinite recycled decimal transform fractions? Because the number of digits in its decimal part is infinite, Obviously, it's impossible to write a few tenths, percentages, thousandths As a matter of fact, it's difficult to make a circular decimal number in infinite decimal places. So I'll start from here and try to "cut off" the "big tail" of the infinite circular decimal. The strategy is to enlarge the infinite circular decimal by 10 times, 100 times or 1000 times Let's make the expanded infinite cyclic decimal exactly the same as the "big tail" of the original infinite cyclic decimal, and then subtract the two numbers, and the "big tail" will be cut off
(1) 0.4747 And 0.33 Turn it into a fraction
Think 1:0.4747 ×100=47.4747……
0.4747…… ×100－0.4747…… =47.4747…… －0.4747……
(100－1)×0.4747…… =47
That is 99 × 0.4747 =47
So 0.4747 =47/99
Think 2:0.33 ×10＝3.33……
0.33…… ×10－0.33…… =3.33… －0.33……
(10-1) ×0.33…… =3
That is 9 × 0.33 =3
So 0.33 =3/9=1/3
Thus, it can be seen that the fractional part of pure cyclic decimal can be written as such: what is the minimum number of digits of the cyclic section of pure cyclic decimal, and the denominator is the number composed of several 9; the numerator is the number composed of one cyclic section of pure cyclic decimal
(2) 0.4777 And 0.325656 Turn it into a fraction
Think 1:0.4777 ×10=4.777…… ①
0.4777…… ×100=47.77…… ②
It can be obtained by using ② - ①
0.4777…… ×90=47－4
So, 0.4777 =43/90
Think 2:0.325656 ×100=32.5656…… ①
0.325656…… ×10000=3256.56…… ②
It can be obtained by using ② - ①
0.325656…… ×9900=3256.5656…… －32.5656……
0.325656…… ×9900=3256－32
So, 0.325656 =3224/9900

When we simplify a fraction, we use 2 about twice and 3 about once to get 38. The original fraction is ()
A. 3696B. 1848C. 2456D. 1632

38 = 3 × 2 × 2 × 38 × 2 × 2 × 3 = 3696

Using the knowledge of earth movement to explain the phenomenon of life and analyze practical problems

Four seasons change, the sun rises in the East and sets in the west, the stars and the moon shift. Etc. when the bathtub and other things are given water, the earth moves from west to East in the northern and southern hemispheres, and the water flow whirlpool occurs. The southern hemisphere is opposite to the Northern Hemisphere, one from west to East, and the other from east to west

Combined with practical problems (such as uneven square table),
The number of words is not less than 300 words. Explain the principle, formula and brief calculation

Brother, give me some points. OK?
I'll give you an answer
-_ -How mean!
If the square table is not stable, set the shape of the table as a square, and at least three feet have touched the ground, and one foot has not touched the ground, resulting in instability. The four feet are recorded as a, B, C, D respectively, and the sum of the distances between a, C and the ground is
The sum of the distances between F (x), B, D and the ground is g (x), and f (x) > = 0, G (x) > = 0, and it is a continuous function. Because there are three feet touching the ground at any time, suppose g (x) = 0, f (x) > 0 when x = 0. Rotate the table 90 ° and exchange the diagonal AC and BD. because g (0) = 0, f (x) > 0, G (π / 2) > 0, f (π / 2) = 0
Let H (x) = f (x) - G (x), so h (0) > 0, H (π / 2)

Which cup of water is sweeter? Try to explain the reason with fractional knowledge. The first cup has 10 grams of sugar and 100 grams of water; the second cup has 15 grams of sugar and 120 grams of water

10÷(10+100)=1/11
15÷(15+120)=1/9
1/11

A cup of 10G sugar, 100g water, another cup of 15g sugar, 120g water. Which cup of water is sweeter? Explain the reason with fractional knowledge

NO.1 10/100 =1/10
NO.2 15/120=1/8
∵1/10

2 / 3 numerator plus 4, how much should be added to the denominator to keep the size of the fraction unchanged (please write down your analysis process and explain what knowledge has been applied))

If the numerator and denominator are multiplied by a number at the same time, its value will not change
The numerator plus 4 is 6, which is three times of the original numerator. In order to keep the score unchanged, the denominator should also be multiplied by 3, which is 9, and the added value is 9-3 = 6

The teacher asked me to sort out the knowledge points of "recognition of scores", such as: what is a score? The comparison of scores? But I still can't do it

Understand the meaning of true fraction, false fraction and with fraction The fraction whose numerator is less than the denominator is true fraction A fraction whose numerator is greater than or equal to the denominator is a false fraction. A false fraction ≥ 1 has the following characteristics: the numerator is larger than the denominator, or the numerator is equal to the denominator

How to organize English knowledge?
The knowledge of English is very scattered and disordered. It can't be sorted into special topics like mathematics and politics. There are also some special words and special usages. When the teacher talks about the topic, every topic is different. Every topic has its own knowledge, and the teacher will expand it. But afterwards, I don't know how to sort it out. I still feel very confused and scattered when I put it in the wrong topic book, Review up no clue, I am now a sophomore, in the second half of the year will be promoted to senior three, how to do this?

I am a senior three students, I usually are classified. In fact, there are a lot of principle test points are the same! For example, predicate verb singular and plural, far or near for a class, virtual for a class But the important thing is to have exercises, put them together and leave some space for supplement

How do inequality symbols change
For example: how to change 2x ≥ - 1
Would you please teach me how to change the sign of inequality? Is there a negative sign on the left or a negative sign on the right?

A:
The key is to see what number is divided by both sides at the same time
If both sides of the inequality are divided by negative numbers, the direction of the inequality sign will change
If both sides of the inequality are divided by positive numbers, the direction of the inequality will not change