What are the 16 simple calculations?

1. Apply the multiplicative distributive law.

Easy to calculate. The multiplicative distributive property refers to:

Example: 38x101, how do we dismantle it? See who is closer to the whole hundred or ten, of course 101 is better, then we can split 101 into 100+1.

38x101

38x（100+1）

38x100+38x1

Second, the benchmark number method.

Find a compromise number in a series of numbers to represent all numbers, and remember that the number should not be selected to deviate from this series of numbers. Example:

2062x5）+10-10-20+21

3. Addition combined with law.

The use of the associative law of addition (a b) c=a (b c) allows for easier operations by changing the position of the additive. Example:

Fourth, the splitting method.

The splitting method is to split a number into several numbers for the convenience of calculation. This requires mastering some "good friends" such as: 2 and 5, 4 and 5, 2 and, 4 and, 8 and so on. Be careful not to change the size of the number! Example:

1) Use the commutative and associative properties of addition to calculate. Students are required to be good at observing the problem and have a sense of neatness.

Such as: , etc. 2) Use the commutative and associative laws of multiplication to make simple calculations.

For example, if you encounter division, the same applies, or change division to multiplication. Such as: , etc.

3) Use the multiplicative distributive law to perform simple calculations, and when encountering a division by a number, it is first reduced to the reciprocal of multiplying a number, and then distributed.

For example, it should also be noted that some of the problems are simplified by using the inverse operation of the distributive law: that is, the common factor is extracted. As.

4) Use the nature of subtraction to make a simple calculation. The nature of subtraction is expressed by a letter formula: a b c = a (b + c), while paying attention to the reverse progression.

For example: 7691 (691+250).

5) Use the nature of division to make simple calculations. The nature of division is expressed by a letter formula as follows: a b c = a (b c), while noting the reverse progression, e.g., 736 25 4.

6) The operation of numbers close to whole hundreds. This type of question requires the cooperation of skills such as splitting and conversion.

As. 302 + 76 = 300 + 76 + 2, 298-188 = 300-188-2, etc.

7) Observe an operation that is 0 or 1.

Such as: , etc. Generally speaking, the idea of simple operation is: (1) the use of the nature of operation, laws, etc. (2) It may disrupt the regular calculation order.

3) The size of the number cannot be changed when splitting or converting. (4) Correctly handle the connection of each step. (5) Quick calculation is also calculation, which is to turn hard calculation into clever calculation.

6) Be able to improve the speed and ability of calculation, and cultivate rigorous, meticulous, flexible and ingenious working habits.

Many times I have breakfast at one time v easy to operate! Tik Tok!

What do you think about this issue? How happy?

Math Easy Calculation Method:

1. Split term method.

Fractional splitting refers to splitting the terms in the fractional equation so that the split items can be offset before and after, and this splitting calculation is called splitting method.

A common method of splitting a number into the sum or difference of two or more numeric units. When encountering the calculation problem of split term, it is necessary to carefully observe the numerator and denominator of each term, find out the same relationship between each numerator and denominator, and find out the common part.

1) The molecules are all the same, the simplest form is 1, and the complex form can be x (x is any natural number), but as long as x is extracted, it can be converted into an operation where the molecules are all 1.

2) The denominator is the product of several natural numbers, and the factors on the two adjacent denominators are "end-to-end".

3) The difference between several factors on the denominator is a fixed value.

Second, the benchmark number method.

In a series of numbers, find a compromised number to represent all the numbers, and remember that the selection of this number cannot deviate from this series of numbers. Example:

2062x5）+10-10-20+21

3. Addition combined with law.

The use of the associative law of addition (a b) c=a (b c) allows for easier operations by changing the position of the additive. Example:

Fourth, the tail removal method.

In the subtraction calculation, if the mantissa of the subtraction and the subtraction are the same, the subtraction of the same mantissa can be used to subtract the subtraction of the same mantissa first. Examples.

In the equation, the second subtraction 256 is the same as the mantissa of the subtracted number 2356, and the positions of the two numbers can be swapped, so that 2356 can be subtracted by 256 first, which can make the calculation easier.

5. Extracting the common factor method.

This method actually uses the multiplicative distributive property to extract the same factors. Example:

Simple calculation is a special kind of calculation, which uses the laws of operation and the basic properties of numbers, so as to make the calculation easy, so that a very complex formula becomes easy to calculate the number.

1. Addition commutative law: the position of two numbers is added and the sum is unchanged.

2. Addition associative law: add three numbers, first add the first two numbers, or add the last two numbers first, and then add with the third number, and the sum is unchanged.

3. Multiplicative commutative law: when two numbers are multiplied, the position and product of the exchange factor remain unchanged.

4. Multiplication and associative law: multiply three numbers, multiply the first two numbers, or multiply the last two numbers first, and then multiply with the third number, and their product remains unchanged.

5. Multiplicative distributive law: multiply two numbers by the same number, you can multiply the two additive numbers with this number respectively, and then add the two products, and the result remains the same. For example: (2+4) 5 2 5+4 56,

Nature of division: In division, the dividend and the divisor expand (or shrink) by the same multiple at the same time, and the quotient does not change. o divided by any number that is not o gives o.

Simple multiplication: multiplication of the multiplier, the multiplier at the end of the o, you can first multiply the front of the o, zero does not participate in the operation, a few zeros are falling, added at the end of the product.

The commutative law of addition. Multiplication assigns green-green.

1 Commutative Law of Addition: a+b=b+a 2 Associative Law of Addition: (a+b)+c=a+(b+c) 3 Commutative Law of Multiplication:

a b = b a 4 multiplicative associative property: (a b) c = a (b c) 5 multiplicative distributive property: a (b + c) = a b + a c

1. A dozen times a dozen:

Formula: head by head, tail by tail, tail by tail.

Example: 12 14=?

Solution: 1 1=1

Note: Multiply the single digits, and use 0 to occupy the place if the two digits are not enough.

2. The head is the same, and the tail is complementary (the sum of the tails is equal to 10):

Formula: After adding 1 to a head, the head is multiplied by the head, and the tail is multiplied by the tail.

Example: 23 27=?

2 Front Balance 1 3

Note: Multiply the single digits, and use 0 to occupy the place if the two digits are not enough.

3. The first multiplier is complementary, and the other multiplier number is the same:

Formula: After adding 1 to a head, the head is multiplied by the head, and the tail is multiplied by the tail.

Example: 37 44=?

Note: Multiplying the single digits, it is not enough for two Hui to bury the number to use 0 to occupy the place.

4. Dozens of one times dozens of one:

Formula: head by head, head by head, tail by tail.

Example: 21 41=?

Multiply by any number: formula: the end does not move to fall, and the sum of the delay between the middle and the liquid is pulled down.

Example: 11 23125=?

2 and 5 are at the beginning and end respectively.

Note: and full ten to one.

6. Multiply any number by a dozen times:

Example: 13 326=?

13 digits is 3

Note: and full ten to one.

In the first grade, children will learn the ten ways to make up, break the ten ways and make the ten peace.

When it comes to making up the ten methods and breaking the ten laws, many parents should still remember the scene of teaching their children vividly!

So what are the Ten Laws, the Ten Laws, and the Ten Laws of Peace?

The mantra of the method of making ten: look at the big number, split the small number, make up ten, and calculate the number;

The mantra of breaking the ten methods: see 9 plus 1, see 8 plus 2, see 7 plus 3, see 6 plus 4, see 5 plus 5, see 4 plus 6, see 3 plus 7, see 2 plus 8, see 1 plus 9;

The flat ten method is a method of calculating the abdication subtraction within 20, which is to divide the subtraction into two numbers, and the subtracted number should be equal to 10 after subtracting the first number, and then use 10 to subtract the second number to get the final result.

In this way, there are actually very few calculation methods that need to be learned in the first grade.

The most important thing in the second grade is the multiplication formula table, it is nothing to memorize, it is important to be able to use, if the child will not be proficient in multiplication, then division will basically not.

One ring after another, interlocking.

In addition to multiplication and division, the second grade is the focus, whole.

10. The calculation of the whole number of hundreds is the expansion of addition and subtraction within 10, the addition and subtraction of the whole number of tens is actually the addition and subtraction of several tens, and the addition and subtraction of the whole number of hundreds is actually the addition and subtraction of several hundreds.

3rd grade. What calculations are the focus?

Probably written arithmetic, didn't the second grade already learn written arithmetic?

But that's just addition and subtraction and simple division, and in the third grade, there are multi-digit multiplied multiplication, and multi-digit division by one-digit.

If you are not proficient in multiplication formulas, you will make mistakes in pen multiplication, and as for pen calculation and division, it is basically a mistake.

The simple operation of the third grade focuses on the rounding method:

For example: 91 + 92 + 93 + 94 + 95 + 105 + 106 + 107 + 108 + 109

1. A dozen times a dozen:

Formula: head by head, tail by tail, tail by tail.

Example: 12 14=?Solution:

Note: Multiply the single digits, and use 0 to occupy the place if the two digits are not enough.

2. The head is the same, and the tail is complementary (the sum of the tails is equal to 10):

Formula: After adding 1 to a head, the head is multiplied by the head, and the tail is multiplied by the tail.

Example: 23 27=?

Solution: 2 1 3

Note: Multiply the single digits, and use 0 to occupy the place if the two digits are not enough.

3. The first multiplier is complementary, and the other multiplier number is the same:

Formula: After adding 1 to a head, the head is multiplied by the head, and the tail is multiplied by the tail.

Example: 37 44=?

Solution: 3+1=4

Note: Multiply the single digits, and use 0 to occupy the place if the two digits are not enough.

4. Dozens of one times dozens of one:

Formula: head by head, head by head, tail by tail.

Example: 21 41=?

Solution: 2 4=8

Multiply by any number: formula: the end does not move down, and the sum of the middle pulls down.

Example: 11 23125=?

Solution: 2+3=5

2 and 5 are at the beginning and end respectively.

Note: and full ten to one.

6. Multiply any number by a dozen times:

Example: 13 326=?

Solution: 13 digits are 3

Note: and full ten to one.

It can be solved by using the formula for summing the series of equal differences (the teacher emphasizes the method of finding the "number of terms") (3) You can split 3 and then combine and 9 respectively to round up. For the second and fourth types, most students find it a little difficult, at this time, I still guide the students to start with the characteristics of the equation, and guide the students to analyze the characteristics of the equation, such as (2) these additions are different but very close, and the students say the strategy they have come up with: you can also use the rounding method to divide the "4" in 54 and the ...... of 47With the help of the spark of the student's thinking, I used the appropriate language to dial, and the student immediately came to the conclusion that these additions can be regarded as 50, and then the difference more than 50 is added, and the difference less than 50 is subtracted.

The students were excited to discover a simple algorithm. In the process of solving (4), the students immediately summarized the characteristics of the equation. It was also found that if the numbers were rearranged, the equation would be obtained as follows:

12 12 (45 45) (72 72) This problem is solved. According to such several types of problems, let the students feel the importance of observing and discovering the characteristics of the arithmetic, on the basis of this, I give the students two words, that is, "flexible", I tell the students, this is the magic weapon of simple operation, only according to the characteristics of the problem to choose the simple algorithm flexibly, you can solve more simple arithmetic problems. For teachers, it is not the most important thing to teach students how many problems to solve, but it is important for students to find the key to unlock the lock, which is a kind of consciousness, a kind of mathematical ideas and methods. Adopt it.

1. A dozen times a dozen:

Formula: head by head, tail by tail, tail by tail.

Example: 12 14=?

Solution: 1 1=1

Note: Multiply the single digits, and use 0 to occupy the place if the two digits are not enough.

2. The head is the same, and the tail is complementary (the sum of the tails is equal to 10):

Formula: After adding 1 to a head, the head is multiplied by the head, and the tail is multiplied by the tail.

Example: 23 27=?

Solution: 2 1 3

Note: Multiply the single digits, and use 0 to occupy the place if the two digits are not enough.

3. The first multiplier is complementary, and the other multiplier number is the same:

Formula: After adding 1 to a head, the head is multiplied by the head, and the tail is multiplied by the tail.

Example: 37 44=?

Solution: 3+1=4

Note: Multiply the single digits, and use 0 to occupy the place if the two digits are not enough.

4. Dozens of one times dozens of one:

Formula: head by head, head by head, tail by tail.

Example: 21 41=?

Solution: 2 4=8

Multiply by any number: formula: the end does not move down, and the sum of the middle pulls down.

Example: 11 23125=?

Solution: 2+3=5

2 and 5 are at the beginning and end respectively.

Note: and full ten to one.

6. Multiply any number by a dozen times:

Example: 13 326=?

Solution: 13 digits are 3

Note: and full ten to one.