How to write a lesson plan for preparing for a lesson, and how to write a lesson plan for a lesson?

Lesson plan, are you a teacher? None of this?

In fact, it is to find the least common multiple of the denominator:

For example, 5 7 and 1 2, 7 and 2 are the denominators, and the least common multiples of 7 and 2 are 2 7 14, 5 7 The numerator and denominator are multiplied by 2 to get 10 14, and 1 2 numerators and denominators are multiplied by 7 at the same time to get 7 14, ok!

The rest tells you that you have gained from practicing the common multiples yourself, and the math is reasonable.

The least common multiple of 3 8 and 3 4 is 8

3 16 and 12 7 least common multiple 16 7

4 9 and 7 18 Least common multiple 18

7 and 3 8 Least common multiple 7 8 5

Directly find out the common number of different denominators, for example, the common number of the denominator of 3 9 and 3 1 is 9.

The numerator is multiplied by the numerator to find the greatest common factor, and the same goes for the denominator.

I don't know, oh, please look it up online!!

Reduction: The process of turning a fraction into a simplest fraction.

General fraction: the process of converting several fractions (formulas) with different denominators into fractions (formulas) with the same denominator equal to the original fractions (formulas) according to the basic properties of fractions (formulas).

Steps for Reduction:1. Decompose the numerator and denominator into factors;

2. Find out the common factor of the numerator and denominator;

3. Eliminate the non-zero common factor.

If you can quickly see the greatest common factor of the numerator and denominator, it is easier to remove them directly by their greatest common divisor. For example.

Steps to pass through:1. Find the common denominator. (The common denominator can be the least common multiple of two or several numbers) 2, and then the denominator of the two or several fractions that need to be divided is changed from a different denominator to the same denominator.

For example, 2 3 and 3 7 pass points, first find the common denominator of 3 and 7, that is, 21, then (2x7) (3x7) = 14 21, (3x3) (7x3) = 9 21, so 2 3 and 3 7 pass are 14 21 and 9 21.

Generally speaking, it is to change the denominator of different fractions to the same, such as calculating 1 3 + 1 2, taking the least common multiple of the common divide, 2 6 + 3 6 = 5 6, and achieving the purpose of calculation by changing the denominator to the same.

Reduction is to cross out the factors of the numerator and the denominator, for example, 6 8, there are factors 2 up and down, and it is divided into 3 4The covenant is used to simplify.

As for how to divide it, it is the numerator and denominator multiplied by the same number (except 0) As for how to divide, that is, the numerator and denominator are divided by the same number (except 0), and the division is used to simplify.

General division (mostly used in addition and subtraction with different denominators) is to multiply the denominator of two fractions into a fraction with the same denominator, and if there is a common divisor, it will be reduced. For example, 1 6, and 1 9, the denominator is multiplied by 54, but there is a common divisor of 3, so to divide by 3, the denominator after the general division should be 18.

Reduction (mostly used for multiplication and division between fractions) is to find the common divisor of the numerator and denominator, and turn it into the simplest fraction, such as 2 9 and 3 10, after multiplication, if it is not divided, it is 6 90, and 6 and 90 have a common divisor 6, so the numerator and denominator are divided by 6, and the simplest fraction is 1 15

Reduction: Reducing a fraction into a number that is equal to it, but the numerator and denominator of the fraction are relatively small, is called reduction;

General score: The fraction with different denominator is converted into a fraction with the same denominator as the original fraction, which is called a universal fraction.

Both the reduction and the general fraction are based on the basic properties of the fraction: the numerator and the denominator expand or decrease by the same multiple (except 0) at the same time, and the fractional value remains the same.

How to divide the fraction by the fraction, the general score and the approximate score.

Reduction is the numerator and denominator divided by the same common divisor.

A common fraction is when the numerator and denominator are multiplied by a number at the same time.

Flexible use of general and reduced points can make the calculation easier!

Your question is a bit too general, be careful.

Top left: 3x 12x 2=(3x 3x) (12x 2 3x)=1 4x

Top right: (x 2-4) (x+2)=(x+2)(x-2) (x+2)=x-2

Bottom left: The least common multiple is 3y*2y=6y2, so they are 2xy 6y2;9x/6y^2

Bottom right: The least common multiple is 2(a+b) 2, so they are (a-b)(a+b) 2(a+b) 2;2ab/2(a+b)^2

Reduction: According to the basic properties of fractions, the numerator and denominator of a fraction are divided by the common factor at the same time, and this process is called reduction.

To put it simply, the process of turning a fraction into a simplest fraction is called an approximate fraction.

Method of Reduction:

1. Decompose the numerator and denominator into factors;

2、.Find the common factor of the numerator and denominator;

3. Eliminate the non-zero common factor.

General score: According to the basic nature of the fraction, the process of converting several fractions with different denominators into fractions with the same denominator as the original fraction is called the general score.

How to pass the points:

1. Find the simplest common denominator of the denominator of the original fractions;

2.According to the basic nature of fractions, the original fraction is converted into a fraction with the simplest common denominator as the denominator.

Reduction: Divide the common divisor of the numerator and denominator (i.e. divide by that number), and continue to reduce if there is still the same factor until there is none.

General fraction: The process of making the denominator of two fractions the same without changing the size of the original number.

The basis for dividing and dividing is the basic nature of fractions, so it is necessary to have a thorough understanding of the basic properties of fractions, that is, the numerator and denominator of fractions are multiplied or divided by an identical number at the same time, and the size of the fraction remains unchanged. In this nature, it is necessary to grasp these key words: simultaneous, the same number, and the size is unchanged.

The method of reduction is to divide the common factor of the numerator and denominator at the same time, and it should be noted here that reduction is a process, as long as the numerator and denominator of the original fraction are divided by their common factor, we can say that the fraction is reduced. However, in general, we require that the result of the reduction score be the simplest score. Therefore, the criteria for judging the reduction score and the minimum score are different, and do not confuse them.

The method of common fraction is to find the common denominator of two fractions, and then convert the two different denominator fractions into equal denominator fractions according to the basic properties of fractions. The key to the common denominator is to find the common denominator and use the common multiple of the two fractional denominators as the common denominator, but usually for the sake of calculation simplicity, we generally use the least common multiple of the two fractional denominators as the common denominator. Here I would like to remind you that some students are affected by the example questions in the textbook, and after scoring the two scores, they will compare the size of the requirements without dividing the questions, which fully illustrates the ambiguity of knowledge.

The general fraction is the process of converting two fractions with different denominators into fractions of the same denominator of equal size, and we can compare the size of fractions with different numerator and denominator. Comparing the size of the fraction is the application of this knowledge, and in the future we will also use the general fraction to calculate the addition and subtraction of the different denominator fraction, so we must not think that the purpose of the universal fraction is to compare the size, this idea is incorrect.

There are generally two ways to divide, one is to remove the common factors of the two numbers one by one, and the other is to directly remove the greatest common factor of the two numbers, both methods can be used.

The key to general division is to find a good common denominator, and to find the lowest common denominator.

Multiplying the numerator and denominator by a number is called a general fraction, and dividing by a loss is called a divide.

The common fraction is to divide the fraction of the different denominator into a fraction of the same denominator that is equal to the original fraction.

Reduction of a fraction: The reduction of a fraction is called reduction of a fraction

Simplest fraction: The numerator divides a fraction into a fraction that is equal to it, but the numerator and denominator are relatively small, which is called a fraction. The numerator and denominator are fractions of coprime numbers (the denominator is not 1), which is called the simplest fraction (also known as the approximate fraction).

Reducing a fraction to a fraction that is equal to it, but with a smaller numerator and denominator, is called a fraction.

Note: When reducing the fraction, try to use oral calculation, generally use the numerator and turn a fraction into a fraction that is equal to it, but the numerator and denominator are relatively small, which is called a fraction. The common divisor of the denominator (except 1).

Remove the numerator and denominator of fractions; It is usually divided until the simplest score is obtained.

If you can quickly see the greatest common divisor of the numerator and denominator, it is easier to remove them directly by their greatest common divisor. Spelling: 2 6 12 — 30 15 5 (all divided numbers are crossed out, as in this example).

Reduction is to be sure to pay attention to find its common divisor, that is, the common divisor of the numerator and denominator, not just simplify the denominator or numerator, the common divisor of the double number must have 2, so you can divide by 2 first, divide slowly, and then add up all your divisions to be their greatest common divisor.

2. The Historical Narrative of the Covenant.

In the ancient Chinese "Nine Chapters of Arithmetic", it is said: "About half can be half of the half." If it is not half, the number of sub-denominators and numerators should be reduced by less, and more by detracting, and so on. Equal numbers. ”

Extended reading: 1 Primary School (Western Normal Edition) Mathematics Volume 10.

2 Primary Mathematics 5th Grade Volume II.

According to the basic properties of fractions, the common fractions are converted into fractions that are equal to the original but have the same denominator, which is called changing fractions to acommon denominator

The method of general fraction: the different denominator fractions are divided into the same denominator fraction as the original, which is called the common fraction.

The ratio of the number A to the number B and the two different ratios of the number B to the number C into the ratio of A to the ratio of B to C is also called a general score.

For example: compare: 7 9 and 8 11 sizes.

A: B = 2:5 = 8:20

B: C = 4:7 = 20:35

A: B: C = 8:20:35