76 101 How to calculate in an easy way.

Easy Calculations The skills and methods of easy calculations are mainly exposed and learned from the fourth grade. The framework is the two laws of addition and the three laws of multiplication. That is, the nature of the commutative law of addition, the law of associativity and subtraction, the commutative law of multiplication, the law of associative combination of multiplication, and the distributive law of multiplication.

Although the content is simple, it is necessary to make it clear as part of the article.

1. The commutative law of addition, that is, the exchange of the positions of two additions, and the invariant. It is represented by letters as a+b=b+a;

2. The associative law of addition, that is, the addition of three numbers, add the first two numbers, or add the last two numbers first, and the result remains the same. It is expressed as (a+b)+c=a+(b+c);

The property of subtraction, i.e., a number subtracting two numbers (or more) in a row, is equivalent to the sum of the numbers minus them. It is expressed as (a+b)+c=a+(b+c);

3. The commutative law of multiplication, that is, the position of two factors is exchanged, and the product is unchanged. It is represented by letters as a+b=b+a;

4. Multiplication associative law, that is, three numbers are multiplied, the first two numbers are multiplied, or the last two numbers are multiplied first, and the result remains the same. It is expressed as (a+b)+c=a+(b+c);

5. Multiplicative distributive law, that is, a number multiplied by the sum (or difference) of two numbers, which is equal to the number multiplied by two numbers respectively, and then the sum (or difference). It is expressed by letters as a(b+c)=ab+ac, or a(b-c)=ab-ac.

In fact, in addition to the above common simple calculation methods, there are also some important simple operation knowledge, which can sometimes be learned in practice problems. For example, 1 (2x3)=1 2-1 3,1 (3x4)=1 3-1 4,1 (4x5)=1 4-1 5,...This series of calculations is often used to solve problems simply.

Similarly, 1 (2x4)=1 2x(1 2-1 4), 1 (3x5)=1 2x(1 3-1 5), this series of calculations is actually the same as the above series of calculations, if students can't find out for themselves, then do they have to list another 1 (2x5)=1 3x(1 2-1 5) series of equations, until infinity?

Therefore, the key to the so-called simple arithmetic is for students to discover and summarize by themselves, relying on teachers or extracurricular books to list them all and let students memorize them by rote.

How do you calculate 222 555 in an easy way?

This is a simple calculation using the distribution ratio, the original formula = 2 5 111 111 = 10 12321 = 123210

Summary. 125 125 15 How to calculate in an easy way.

The simple calculation method is as follows, you can refer to it, if you don't understand something, you can ask me, dear.

The simple calculation process method is as follows, and 39 is regarded as (40-1) imitation.

Gear Solution: 39 202

Note: Write 48 5 48 as (48 5) 48, and the accompaniment can make the operation easy to disperse.

Summary. Because it is inexhaustible, the denominator is retained.

720 19 27 How to calculate in an easy way.

Hello, 720 19 27 how to calculate in a simple way, the details are as follows:

Because it is inexhaustible, the denominator is retained.

The result was 19/19440

The fourth grade of primary school has not yet learned the score.

The topic is not wrong, otherwise this is inexhaustible, and it can only be decimalized.

As follows: 35 102 Vertical of math problems.

The simple operation steps are as follows: