How to add and subtract different denominator fractions, and how to add or subtract different denomi

In the addition and subtraction of fractions with different denominators, the fractions must first be divided into fractions with the same denominator, and then calculated according to the method of addition and subtraction of fractions with the same denominator.

To add and subtract fractions, the first step is to review the question and observe whether the fractions have the same denominator or different denominator. If it is the addition and subtraction of different denominator fractions, you need to perform the general division first, and then the addition and subtraction operations. The final calculation result can be reduced to the offer score of the fraction into the simplest fraction, and the result is that the false fraction is reduced to a fraction or an integer.

The addition and subtraction of fractions is in the same order as that of integers, and when there are no parentheses, they are performed from left to right; If there are parentheses, the inside of the parentheses is counted first, and then the outside of the parentheses is calculated.

For example: 1 3 + 1 4 = 4 12 + 3 12 = 7 12

The numerator and denominator are multiplied by the same non-zero number at the same time, and the value of the fraction does not change, according to this, the numerator and denominator are multiplied by the common multiple of the denominator. For example: 1 3+2 5=1*5 3*5+2*3 5*3=5 15+6 15=11 15

I hope it helps.

The denominator is divided, and the numerators are added.

First, find the least common multiple of the denominator.

There's basically no easy way to fix it, unless you're stumbling into a well-designed problem??? ps: It seems that I didn't) Anyway, I used to be stupid and still looking for an easy way, and I did it randomly, and the result was still a pass.

Tongfen ha

Here are 20 questions about addition and subtraction of fractions with different denominators.

When the fraction of the different denominator is added or subtracted, the score of the different denominator is calculated according to the calculation method of the addition and subtraction of the fraction of the same denominator.

General method: 1. Find the least common multiple of the denominator of the original fractions.

2. According to the basic nature of the fraction, the original fraction is converted into a fraction with this least common multiple as the denominator;

The rule of addition and subtraction of fractions with different denominator is: first pass the fraction, and then calculate according to the rule of addition and subtraction of fractions with the same denominator.

Then it is calculated according to the calculation rule of addition and subtraction of the same denominator fraction: first pass the score, when the denominator is not the same, the addition and subtraction of the different denominator fraction should be passed first.

First, the score is divided into fractions with the same denominator, and then added and subtracted according to the law of addition and subtraction of fractions with the same denominator.

The calculation of the addition and subtraction of the fraction with different denominator is to first pass the fraction, (find the least common multiple of the denominator) into the addition and subtraction of the same denominator, and then calculate.

1. Pass first. Turn a different denominator fraction into a fraction with the same denominator. 2. Add and subtract. Add or subtract according to the method of adding and subtracting fractions with the same denominator. (The denominator remains unchanged, the numerator is added and subtracted) such as: 7 8-2 3=21 24-16 24=5 24

Multiply each other with the denominator, multiply the number of times the numerator, and finally compare with the same denominator, and it's OK.

The addition and subtraction of different denominator fractions is calculated according to the law of addition and subtraction of fractions with the same denominator, the denominator remains unchanged, the numerator is added and subtracted, and finally the fraction is reduced.

General division method: add and subtract the fractions of different denominators, find the least common multiple of each denominator, and the mutated denominator is the same denominator; Use the law of addition and subtraction of fractions of the same fraction: that is, the denominator does not change, and the fraction is added and subtracted; The results are obtained by differentiating the results into the simplest fraction approximately.

Find the least common multiple of the denominator of the original fractions; According to the basic nature of fractions, the original fraction is reduced to a fraction with this least common multiple as the denominator.

The concept of heteronominator fractions: it is two or more fractions, their denominators are different, they are called heterodenominators, and they have nothing to do with the numerator, for example: 3 and 3 4, these three fractions have different denominators, so they are heterodenominator fractions.

The addition and subtraction of fractions is in the same order as integers, and when there are no parentheses, they are carried out from left to right.

We've said this before, but our thoughts are the same, this is not the main thing.

If it is a mixed cyclic decimal, there are several cyclic sections, and the denominator has several 9s; There are several digits that are not cyclical, and there are several zeros after 9, and the numerator is the difference between the number of the decimal part before the second cyclic section and the number of the non-cyclic part of the decimal part. e.g. cyclical) = (12-1) 90 = 11 90.

The addition and subtraction of different denominator fractions, that is, the use of the basic properties of fractions to convert different denominator fractions into fractions of the same denominator, change the unit of fractions without changing the size, and then calculate according to the addition and subtraction of fractions of the same denominator, and finally the offer score that can be reduced.

The fraction is divided by an integer, the denominator remains unchanged, if the numerator is a multiple of an integer, the numerator is divided by the integer, and finally the offer score that can be reduced to a fraction.

The fraction is divided by an integer, the denominator does not change, if the numerator is not a multiple of the integer, then multiply this fraction by the reciprocal of the integer, and finally the offer fraction that can be reduced.

On real numbers, you can define a function that takes a value of 1 for positive numbers, 1 for negative numbers, and 0 for a value of 0. This function is often referred to as a symbolic function.

Negative numbers are marked with a negative sign " " and a positive number, such as 2, which represents the opposite of 2. A negative number is the opposite of its absolute value. On the number axis, negative numbers are to the left of 0.

Rational numbers are a collective term for integers (positive integers, 0s, negative integers) and fractions, and are a collection of integers and fractions, i.e., the decimal part of a rational number is a finite or infinite cyclic decimal number.

Rational numbers correspond to irrational numbers (real numbers that are not rational numbers are called irrational numbers), and their decimal parts are infinite non-cyclic numbers. Rational numbers are one of the important contents in the field of "number and algebra", and they are also widely used in mathematics, which is the basis for continuing to learn real numbers, algebraic formulas, equations, inequalities, Cartesian coordinate systems, functions and other mathematical content and related subject knowledge.

The addition and subtraction of the fraction of the different denominator needs to be divided first, and the denominator is the same, and then the denominator remains unchanged, and the numerator is added and subtracted.

The fractional property numerator and denominator are multiplied by a number at the same time, and their values remain unchanged.

3-1/4=1/12；The least common multiple of 3 and 4 is 12, after the general division the denominator is twelve, and the numerator is 4 minus 3 and the result is 1, so the final result is 1 12.

5+1/7=12/35；The least common multiple of 5 and 7 is 35, the denominator is 35 after the general fraction, and the numerator is 7 plus 5 and the result is 12, so the final result is 12 35.

5-1/7=2/35 ；The least common multiple of 5 and 7 is 35, the denominator is 35 after the general fraction, and the numerator is 7 minus 5 and the result is 2, so the final result is 2 35.

4+1/9=13/36 ;The least common multiple of 4 and 9 is 36, the denominator is 36 after the general fraction, and the numerator is 9 plus 4 and the result is 13, so the final result is 13 36.

4-1/9=5/36 ；The least common multiple of 4 and 9 is 36, the denominator is 36 after the general division, and the numerator is 9 minus 4 and the result is 5, so the final result is 5 36.

Some other additions and subtractions of different denominators are listed below:

For the addition and subtraction of different denominator fractions, the denominator needs to be divided first, and then the addition and subtraction operations are performed.

1. Addition of different denominator fractions: add the fractions of different denominators, and then divide them, and then add the numerators, the denominator does not change, and the result of the calculation, the offer points that can be reduced to the fractions, and the false fractions should be turned into fractions or integers.

Subtraction of different denominator fractions: to subtract the different denominator fractions, and then pass the fractions, and then subtract the numerators, the denominator does not change, and the result of the calculation, the offer fraction that can be reduced, and the false fraction should be turned into a band fraction or an integer.

2. Addition of fractions with the same denominator: as long as the numerators are added, the denominator does not change, and the result of the calculation, the offer score that can be reduced to the fraction, and the false fraction should be turned into a fraction or an integer.

Subtraction of fractions with the same denominator: to subtract the numerator, the denominator should not change, the result of the calculation, the offer score that can be reduced, and the false fraction should be turned into a fraction or an integer.

3. Mixed addition and subtraction of fractions: those with different denominators should be first transformed into the same denominator, and then added and subtracted in order.

Fraction multiplication algorithm.

1. When multiplying fractions by integers, the numerator of fractions and the product of multiplying integers are used as numerators, and the denominator remains unchanged. Those who can make an appointment must first make an appointment.

2. When multiplying fractions by fractions, use the product of the multiplication of the numerators as the numerator, and the product of the multiplication of the denominator as the denominator.

3. When multiplying fractions by decimals, you can turn fractions into decimals, or you can turn decimals into fractions.

The meaning of multiplying fractions by integers is the same as that of integer multiplication, which is to find the simple operation of finding the sum of several identical additions. Multiplying a number by a fraction can be seen as finding out what fractions of the number are.