The definition of the 5th grade score, the trick of the 5th grade score

The definition of the common division is to convert the different denominator fraction into the same denominator fraction equal to the original size, so as long as it is a common multiple to achieve the purpose of the common divide, and taking the least common multiple is only the easiest way.

The fraction with different denominator is divided into fractions with the same denominator that are equal to the original fraction, which is called a common fraction.

The least common multiple of the denominator is 120

3/10 = 36/120

5/8 = 75/120

5/6 = 100/120

3/8 = 45/120

11/12 = 110/120

So 3/10 3/8 5/8 5/6 112/12Judgment. The approximate hour-minute value remains the same, and the through-minute value-minute value becomes larger.

Fractions with different denominators are not easy to directly compare because they have different fractional units. (√

Reduction is done separately for each fraction, and general scoring is done in two or more fractions. ( Only the least common multiple can be used as the denominator after the pass-by.) ( General fraction is the process of fractioning different molecules into the same fraction of the component, and the fraction of the molecule is the same.

3.Scores. The least common multiple of the denominator is 60

1/3 = 20/60

3/10 = 18/60

5/20 = 15/60

If you don't understand, please ask, and I wish you a happy study!

If the denominator of two fractions is equal, and the denominator of each is several times the original, then the numerator will be several times the original.

Fifth gradeScores. Here's the trick:

1. List the divisors of each denominator separately.

2. Multiply the divisor of each denominator, if there is a common divisor.

Multiply it only once, and the result is the least common multiple of each denominator.

3. Whenever a letter appears or a factor containing a letter.

The factor of the power of the base should be taken.

4. The factor of the power of the same letter or the factor containing the letter takes the largest exponent.

5. Multiply all the above formulas to get the simplest common denominator.

Scoring methodAccording to the basic nature of fractions, the original fractions are converted into fractions with this least common multiple as the denominator.

For example: 3 15, 7 18.

The least common multiple of 15 and 18 is 90.

Converting several fractions with different denominators into fractions with the same denominator as the original fractions is called a common fraction. Steps for the 5th grade general score:

First, find the simplest common denominator of the denominator of the original fractions;

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

General knowledge points:

1.The meaning of common multiples and least common multiples: the common multiples of several numbers are called the common multiples of these numbers; The smallest of these numbers is called the least common multiple.

2.How to find the least common multiple of two numbers:

1) Enumeration.

2) Find the multiple of the larger number of the two numbers first, circle the multiple of the smaller number in order from smallest to largest, and the first one is their least common multiple.

3) Decompose the prime factor method.

4) Short division.

3.(1) A special method for finding the least multiple of two numbers: when two numbers are multiples, the larger number is the least common multiple of these two numbers.

2) When two numbers are coprimes, the product of these two numbers is their least common multiple.

4.The meaning of the common score: the fraction of the different denominator is divided into the same denominator fraction equal to the original fraction, which is called the common fraction.

5.The method of general division: the common multiple of the original denominator is used as the common denominator, and the least common multiple is generally used as the common denominator, and then each fraction is converted into a fraction with the smallest common denominator as the denominator.

The general score uses the knowledge that has been learned: the least common multiple, the basic properties of fractions, and the comparison of fractions with the denominator.

The meaning of the general division and the covenant division:

1. Reduction is to divide a fraction into a fraction that is equal to it but the numerator and denominator are relatively small, generally in a fraction. Reduction is used to reduce fractions. For example:

5 20, this fraction is not the simplest fraction form, it can be made into the simplest fraction form by reducing the score 1 4.

2. The general score is to convert multiple different denominator scores into the same denominator fraction with the same size as the original size. The common fraction is used to calculate the fraction of the different denominator. For example: 1 2 + 1 3 = 3 6 + 2 6 = 5 6 (where 1 2 becomes 3 6 is the process of general division).

The key to the general division is to determine the simplest common denominator of several fractions, and the steps are as follows:

1. List the divisors of each denominator separately.

2. Multiply the divisor of each denominator, if there is a common divisor, multiply it only once, and the result obtained is the least common multiple of each denominator;

3. All the factors that appear in the letters or the power of the factors containing the letters should be taken;

4. The factor of the power of the same letter or the factor containing the letter takes the largest exponent.

5. Multiply all the above formulas to get the simplest common denominator.

In the process of calculating the common denominator, the simplest common denominator is first found, and then the fraction is converted into a fraction with the simplest common denominator as the denominator.

1. Find the simplest common denominator of the denominator of the original fractions (formulas);

2. According to the basic properties of fractions (formulas), the original fractions (formulas) are transformed into fractions (formulas) with the simplest common denominator as the denominator.

Compare: 7 9 and 8 11 sizes.

Solution: The simplest common denominator of sum 11 is 9 11 = 99.

Because 77 99 > 72 99, then 7 9 > 8 11.

Notes:

1. The numerator and denominator of the fraction (formula) are multiplied or divided by a number (formula) that is not equal to zero, and the size of the fraction (formula) remains unchanged. The denominator does not change, and the numerator and denominator of the other side are cross-multiplied.

2. Try to use oral calculation when passing the fraction, and generally use the common divisor of the numerator and denominator (except 1) to multiply the numerator and denominator of the fraction; It is usually multiplied until the simplest common denominator is obtained.

The trick to the formula is divided:1. Find the common denominator. (The common denominator can be the least common multiple of two or more numbers.)

2. Then the denominator of two or more fractions that need to be divided is changed from a different denominator to the same denominator. According to the basic nature of fractions: the numerator and denominator of fractions are multiplied or divided by the same number at the same time (except zero), and the size of the fraction does not change.

The key to the general division is to determine the simplest common denominator of several fractions, and the steps are as follows:

1. List the divisors of each denominator separately.

2. Multiply the divisor of each denominator, if there is a common divisor, multiply it only once, and the result obtained is the least common multiple of each denominator;

3. All the factors that appear in the letters or the power of the factors containing the letters should be taken;

4. The factor of the power of the same letter or the factor containing the letter takes the largest exponent.

5. Multiply all the above formulas to get the simplest common denominator.

A common fraction is a fraction with several different denominators that is converted into a fraction with the same denominator and the value remains the same. The same denominator after the common division is called the common denominator, and the lowest common multiple of each fractional denominator is usually used as the common denominator.

For example: 1 2 and 1 3

The process is as follows:

1. Look for the least common multiple of the denominator 2 and the denominator 3, the least common multiple of 2 and 3 is 6.

2. The denominator is reduced to the least common multiple, and the numerator is multiplied by the denominator. 1/2=（1×3）/（2×3），1/3=（1×2）/（3×2）。

2=3/6，1/3=2/6。(The two fractionals are the same as the denominator, and the general fraction solution is completed).

How to calculate the score of the fifth grade is as follows:

A common fraction is a process in which the denominator of two or more fractions is changed to the same number, so that King can add or subtract fractions. Here's how to score 5th grade math:

First, the denominator of fractions is decomposed into prime factors, and then their least common multiple (LCM) is found as the denominator of the general fraction. The least common multiple is the smallest of the common multiples of multiple numbers. For example, if you want to divide 2 3 and 3 4 passes, you can do so by following these steps:

Step 1: Break the denominator into prime factors.

Step 2: Find the least common multiple of the beam differences.

Thus rubber, 12 is the least common multiple of 2 3 and 3 4.

Step 3: Change the denominator of both fractions to 12, and multiply the numerator by the corresponding number so that the value of the fraction does not change.

Now, both fractions have a denominator of 12, and you can add or subtract them, resulting in:

Because 17 12 can no longer be reduced, this result is the simplest form of fraction.

Therefore, the steps of general division can be summarized as:

1.the denominator prime factor of the decomposition fraction;

2.Find the least common multiple of these denominators as the denominator of the common denominator;

3.Multiply the numerator and denominator of each fraction by the appropriate number so that the denominator is equal to the least common multiple;

4.For two or more fractions, the general score is carried out separately, and then the addition and subtraction operations are performed to obtain the final result.