1, quick calculation 1: quick mental arithmetic.
Fast calculation 1: fast mental arithmetic-a teaching mode that is really synchronized with primary school mathematics textbooks.
The quick center is the only way to perform simple operations without any physical objects, and it is not necessary to practice abacus, wrench fingers and abacus.
The arrangement and difficulty of the textbook "Fast Mental Arithmetic" is a fast calculation that closely follows the syllabus of primary school mathematics and integrates with junior high school algebra, which is simpler than the primary school textbook. Simplify written calculation and strengthen oral calculation. It is simple, easy to learn and interesting. After a short period of training, primary school students can write answers directly by adding, subtracting, multiplying and dividing, not vertically.
Special effect of quick mental arithmetic
I have learned all the multiplication, division, addition and subtraction of any multi-digit number above grade three.
Addition and subtraction of high two digits, multiplication of two digits, division of one digit.
First grade, multi-digit addition and subtraction.
Kindergarten large classes learn multi-digit addition and subtraction, tailor-made for preschool children, and pass the primary school oral calculation in advance. Children quickly learn mental arithmetic in kindergarten, which will help them to go to primary school in the future. Children don't do homework with draft paper, but write answers directly.
Fast mental arithmetic is different from abacus mental arithmetic and palm mental arithmetic. Fast mental arithmetic invented by Xi 'an teacher Niu Hongwei. (Teacher Niu Hongwei obtained the patent certificates issued by People's Republic of China (PRC) and China National Intellectual Property Administration. Patent number; ZL200830 1 174275。 Protected by the Patent Law of People's Republic of China (PRC). ) mainly through certain rules in textbooks, children are trained to perform fast operations of addition, subtraction, multiplication and division. "Quick mental arithmetic" is helpful to improve the order, logic and sensitivity of children's thinking and behavior, and train children's eyes, hands and brain to react synchronously and quickly. The calculation method is consistent with mathematics in primary and secondary schools, so it is very popular with parents of young children.
Fast mental arithmetic teaching mode that is really synchronized with primary school mathematics textbooks;
1: learning algorithm-written arithmetic training. At present, China's education system is exam-oriented education, and the standard for testing students is exam transcripts. Then the students' main tasks are to take exams, answer questions and write with a pen. Written arithmetic training is the main line of teaching. Consistent with the mathematical calculation method in primary schools, it does not use any physical calculation, and can be used freely horizontally and vertically, even adding and subtracting. Computing with a pen is the golden key to opening an intelligent express train.
2. Clear the math-math battle. Being able to write questions with a pen not only helps children understand arithmetic, but also helps them understand it. Let children understand the calculation principle and break through the calculation of numbers in spelling. The child completes the calculation on the basis of understanding.
3. Practice speed-speed training, it is far from enough to use a pen to calculate problems. There should be a time limit for oral calculation in primary schools. It takes time to tell whether it is up to standard, that is, there are not enough calculation problems, mainly to speed up.
4. Enlightenment wisdom-intellectual gymnastics is not a simple study and calculation, but focuses on cultivating children's mathematical thinking ability, fully stimulating the potential of the left and right brains and developing the whole brain. After rapid mental arithmetic training, preschool children can deeply understand the essence of mathematics (including), the meaning of numbers (cardinal number, ordinal number, including), the operation mechanism of numbers (addition and subtraction of numbers with the same number) and the way of mathematical logic operation, so that children can master the method of dealing with complex information decomposition and develop divergent thinking and reverse thinking. The child's brain works fast.
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2, quick calculation 2: Swallow gold in the sleeve
Quick calculation 2: In the CCTV hit drama "Going West", tofu flower praised Ching Tien Association for its quick calculation of "swallowing gold in the sleeve" many times. (that is, you don't need an abacus for calculation)! So what is the speed algorithm of swallowing gold in the sleeve?
Swallowing gold in the sleeve is a quick calculation method and a numerical calculation method invented by ancient businessmen in China. The sleeves of ancient clothes were hypertrophy, and only two hands were in the sleeves when calculating, which was called swallowing gold in the sleeves. There used to be a ballad about this calculation method; "Swallowing gold on the sleeve is as wonderful as a fairy, and the number of fingers is moving. You learn priceless treasures, but your bosom friends don't pass them on."
The algorithm of swallowing gold in the sleeve is a folk palm calculation method. Businessmen in China do math, while Shanxi businessmen do accounts while walking. Ten fingers are an abacus, so Shanxi people always swallow a pair of hands in their sleeves for fear of revealing his economic secrets. In the past, in order to make a living, people would not easily spread the secret of this algorithm, and a fast calculation method called "swallowing gold in the sleeve", which has been circulating in China for at least 400 years, is also on the verge of extinction.
According to relevant data, in A.D. 1573, a scholar named Xu Xinlu wrote a book "The Pearl Plate Algorithm", which first described the rapid calculation of swallowing gold into the sleeve; In A.D. 1592, a mathematician named Cheng Dawei published a book, Algorithm Planning, which described the swallowing of gold in the sleeve in detail for the first time. Later, merchants, especially Shanxi merchants, popularized this ancient quick calculation method. The algorithm of "swallowing gold in the sleeve" is a stunt of Shanxi's bank secrecy, and some big merchants and shopkeepers in xi 'an know this fast algorithm.
The method of quickly calculating numbers by swallowing gold into the sleeve is to use five fingers of the left hand as the digital dial, each finger represents a number, and five fingers can represent five numbers: one, ten, hundred, thousand and ten thousand. The upper, middle and lower segments of each finger respectively represent the number 1-9. Arrange three numbers on each section, and the arrangement rules are divided into three columns: left, middle and right. Fingers are arranged upside down on the left (from bottom to top), 1, 2, 3; Fingers are arranged upside down (from top to bottom) in the middle, 4, 5, 6; Fingers are arranged upside down, 7, 8, 9. The calculation method of swallowing gold in the sleeve is a method of using mental arithmetic to reproduce the calculation process with the image of the brain and get the result. It regards the left hand as a virtual abacus with five gears, and clicks the virtual abacus with the right hand to calculate. When counting, point the fingers of your left hand with the fingers of your right hand. Its clear division of labor is: right thumb/left thumb, right index finger, left middle finger, right ring finger, left ring finger and right little finger. The corresponding professional division of labor does not interfere with each other. Which finger is clicked, which finger is extended, and which finger is not clicked, bending, indicating 0. It doesn't need any calculation tools, and it doesn't list arithmetic programs. It only needs to close two hands gently to know the answer number, and can perform four operations of addition, subtraction, multiplication and division on any number within100000 digits.
Swallowing gold in the sleeve, its operation speed (after a certain period of practice, of course) can be comparable to that of an electronic computer, multiplication and division are faster than abacus calculation, and square calculation is much faster than pen calculation. Although for beginners, using' swallowing gold in the sleeve' to calculate simple data is not as fast as a calculator, after mastering this skill, the calculation speed is even faster than a calculator. Someone once calculated the speed of the' swallowing gold in the sleeve' algorithm. A person skilled in this skill will get a 3-to 4-digit multiplication result, which takes about 2 seconds. The result is 5 to 7 digits, about 7 seconds;
Although the algorithm of swallowing gold into the sleeve is born out of abacus, compared with abacus, it does not need any tools, only uses one pair of hands. Because it has the characteristics of "swallowing gold in the sleeve" without tools and eyes, it is very suitable for field work and can also be used in the dark, especially for the blind, and some problems can be solved through this algorithm. "As the saying goes,' ten fingers are connected to one heart', training calculation skills with fingers can exercise bones and muscles, and clever thinking can promote the mind and improve brain power."
Nowadays, businessmen don't have to swallow gold into their sleeves to settle accounts. However, some educators have applied this method to the field of early childhood education. Teacher Niu Hongwei of Xi 'an has been engaged in education for many years, which has improved the swallowing of gold in his sleeve. Make learning easier, more convenient and faster. He has taught thousands of children to learn the improved "swallowing gold in the sleeve". It has a good effect in inspiring children's intelligence. Swallowing gold in the sleeve-developing the child's whole brain. Swallowing gold in the sleeve is not a special function, but a scientific teaching method. More magical than abacus mental arithmetic. It uses hands and brains to complete the fast calculation of addition, subtraction, multiplication and division with amazing speed and high precision. It effectively develops students' brains and stimulates their potential. Innovative fast calculation of swallowing gold in sleeve —— whole brain palmprint calculation —— Niu Hongwei obtained the patent certificate issued by People's Republic of China (PRC) and China National Intellectual Property Administration on May 6th, 2009. Patent number; ZL200830 1 164377。 . Protected by the Patent Law of People's Republic of China (PRC).
The speed algorithm of swallowing gold in the sleeve reduces the complicated calculation process of the pen calculation formula, saves time and effort, and improves the calculation speed of students. You can calculate the addition, subtraction, multiplication and division of any number within100000 digits by hand and brain, and use it to quickly complete the calculation of addition, subtraction, multiplication and division with high accuracy. After two or three months' study, with calculations like 64983+68496 and 78×63, junior children can blurt out the answers with their hands folded.
Innovate the algorithm of swallowing gold in the sleeve-the whole brain palm is a way for children to remember it in their hands and work it out in their minds. Without any calculation tools, they will know the answer with their hands folded. This method is to count the knuckles of the left hand by simulating the bead counting gear on the abacus, and use the left hand as a "five-gear abacus" and use the right hand to draw beads, thus making the human hand a perfect calculator. Students can calculate the result of 100 thousand digits in the calculation process, which is easy to understand and learn. It can really exercise children's brain, heart and hands, and improve their computing ability, memory and self-confidence.
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3, quick calculation 3: Montessori quick calculation
Quick calculation 3: Montessori quick calculation is the development and innovation on the basis of Montessori mathematics, which is relatively young, and "Montessori quick calculation" is aimed at preschool children. The biggest advantage is that children are well connected, which is consistent with the calculation method of primary school mathematics. Suitable for kindergarten middle school children and primary school students.
Montessori's fast calculation can make children deeply understand the basic principle of digital calculation in play. In this way, it is easy to break through children's mathematical calculations. The calculation of numbers includes abstract thinking such as inclusion, classification, decomposition and merger, induction and symmetrical logical reasoning. However, preschool children can only think in images and cannot understand and reason, so it is very difficult for preschool children to learn calculation. The birth of the Montessori Fast Calculation Card enables the principles of mathematical calculation to be presented to children in the form of images. When children understand arithmetic, natural calculation will be simple. The spelling of the numbers 5 and 6 not only shows the answer, but also shows why you should carry it. This is the latest invention patent of Mr. Xi An Niu Hongwei, Montessori Quick Calculation (patent number: ZL200830 1 164396). Its card contains four information: the writing method of number, the shape of number, the amount (base) of number and number. Thereby easily leading children into the interesting digital kingdom.
Montessori quick calculation-the calculation principle is simple, which fully conforms to the national nine-year compulsory education curriculum standard, so that 4.5-year-old children can learn addition and subtraction within 10 thousand in one semester. Montessori's quick calculation starts with the most basic concept of number, which is consistent with the mathematical calculation method in primary schools. But the teaching method is simple, and students are easy to learn and accept. The relaxed and pleasant Montessori quick calculation teaching uses digital images such as cartoons and objects to visualize abstract and boring mathematical concepts and simplify complex problems. Montessori fast calculation is a new method to connect the best math courses for children and improve their math quality.
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4. Fast calculation 4: Fast calculation of special numbers
Fast Calculation 4: Fast Calculation of Conditional Special Numbers
Fast calculation skills of two-digit multiplication
Principle: Let two digits be 10A+B and 10C+D respectively, and their product is s, which is expanded by polynomial:
S = (10a+b) × (10c+d) =10a×10c+b×10c+10a× d+b× d.
Note: Below, "-"stands for ten digits and one digit, because the number obtained by multiplying the ten digits of two digits is followed by two zeros. Please don't forget that the first product is the first two digits, the second product is the last two digits and the middle product is the middle two digits.
A. Fast multiplication
First, the top few are the same:
1. 1. The ten positions are 1, and the positions are complementary, that is, A = C = 1, B+D = 10, s = (10+b+d) ×/.
Method: One hundred digits are two, one digit is multiplied, and the number is the last product, and the first one is full.
For example: 13× 17
13+7 = 2-("-"is used as a mnemonic when you are not proficient, but you can use it when you are proficient)
3 × 7 = 2 1
-
22 1
That is, 13× 17= 22 1.
1.2. The decimal digit is 1, and the digits are not complementary, that is, A = C = 1, B+D ≠ 10, s = (1b+d) ×/kloc-.
Methods: The digits of the multiplier are added with the multiplicand, and the number is the front product. Multiply the digits of two numbers, and the number is the last product, full ten and first.
For example: 15× 17
15+7 = 22-("-"is used as a mnemonic when you are not proficient, but you can use it when you are proficient)
5 × 7 = 35
-
255
That is 15× 17 = 255.
1.3. Ten bits are the same and the bits are complementary, that is, A = C, B+D = 10, S = A× (A+1)×10+A× B.
Methods: Add 1 to ten digits, and multiply the sum by ten digits. The number is the front product, the number is multiplied by single digits, and the number is the back product.
For example: 56 × 54
(5 + 1) × 5 = 30- -
6 × 4 = 24
-
3024
1.4. Ten bits are the same, but the bits are not complementary, that is, A = C, B+D ≠ 10, s = a× (a+1)×10+a× b.
Methods: The first two multiplications, the number is the first product and the number is the last product. Multipliers add up, depending on their size, multiply the first of several multipliers by ten, and vice versa.
For example: 67 × 64
(6+ 1)×6=42
7×4=28
7+4= 1 1
1 1- 10= 1
4228+60=4288
-
4288
Method 2: Multiply the first two digits (that is, find the square of the first digit), the number obtained is the front product, the sum of the two mantissas is multiplied by the first digit, and the number obtained is the middle product. When the decimal number is full, multiply the two mantissas, and the number obtained is the back product.
For example: 67 × 64
6 ×6 = 36- -
(4 + 7)×6 = 66 -
4 × 7 = 28
-
4288
Second, after the same number:
2. 1. One bit is 1 and ten bits are complementary, that is, B = D = 1, a+c =10s =10a×/kloc-0+/kloc-0.
Methods: Multiply ten digits to get the product, and add 10 1.
- -8 × 2 = 16- -
10 1
-
170 1
2.2. < not very simple > the unit is 1, and the ten digits are not complementary, that is, B = D = 1, a+c ≠10s =10a×/kloc-0+.
Methods: The product of ten digits plus the sum of ten digits is the front product, and the unit is 1.
For example: 7 1 ×9 1
70 × 90 = 63 - -
70 + 90 = 16 -
1
-
646 1
2.3 bit is 5, and ten bits are complementary, that is, b = d = 5, a+c =10s =10a×10c+25.
Method: The product of ten digits plus the sum of ten digits is the front product, plus 25.
For example: 35 × 75
3 × 7+ 5 = 26- -
25
-
2625
2.4<'s not very simple > the unit is 5, and the ten digits are not complementary, that is, b = d = 5, a+c ≠10s =10a×10c+525.
Methods: Multiply two digits (that is, find the square of digits), the number obtained is the front product, the sum of twenty digits is multiplied by one digit, and the number obtained is the middle product. When the digits are full, multiply the two mantissas, and the number obtained is the back product.
For example: 75 ×95
7 × 9 = 63 - -
(7+ 9)× 5= 80 -
25
-
7 125
2.5. The positions are the same and the ten positions are complementary, that is, B = D, a+c =10s =10a×10c+b100+B2.
Methods: Ten digits multiplied by ten digits plus one digit is the front product, and one digit is added to the square.
For example: 86 × 26
8 × 2+6 = 22- -
36
-
2236
2.6. One is the same and ten are not complementary.
Methods: Multiply ten digits by one digit, the number is the front product, and add one square, and then see how much the sum of ten digits is greater or smaller than 10. Add a few bits to multiply a large number by ten, and vice versa.
For example: 73×43
7×4+3=3 1
nine
7+4= 1 1
3 109 +30=3 139
-
3 139
2.7. Non-complementary speed algorithm with the same number of digits and ten digits 2
Method: multiply the head by the square of the head and the tail, plus the result of multiplying the head and the tail by the tail and then multiply it by 10.
For example: 73×43
7×4=28
nine
2809+(7+4)×3× 10=2809+ 1 1×30=2809+330=3 139
-
3 139
Third, the special type:
3. 1, the number of a factor is the same from beginning to end, and the ten digits of a factor are multiplied by two digits with complement.
Methods: Add 1 to the first digit of complement, multiply the sum by the first digit of multiplicand, the number is the front product, the two mantissas are multiplied, the number is the back product, and there is no ten digits to complement 0.
For example: 66 × 37
(3 + 1)× 6 = 24- -
6 × 7 = 42
-
2442
3.2. The number of a factor is the same from beginning to end, and the ten digits of a factor are multiplied by two digits that are not complementary to each other.
Methods: Add 1 to the first digit of the random number, and multiply the sum by the first digit of the multiplicand. The number is the front product, and the two mantissas are multiplied, and the number is the back product. If there are no ten digits, add 0. Then see how much the sum of non-complementary factors is larger or smaller than 10, and multiply several numbers with the same number by ten, and vice versa.
For example: 38×44
(3+ 1)*4= 12
8*4=32
1632
3+8= 1 1
1 1- 10= 1
1632+40= 1672
-
1672
3.3. The numbers of a factor are complementary from beginning to end. Ten numbers of a factor are multiplied by two numbers with different digits.
Methods: Add 1 to the first digit of the multiplier, and multiply the sum by the first digit of the multiplicand. The number is the front product, and the two mantissas are multiplied, and the number is the back product. If there are no ten digits, add 0. Then look at how much the tails of different factors are bigger or smaller than the heads, multiply the heads of several remainders by ten, and vice versa.
For example: 46×75
(4+ 1)*7=35
6*5=30
5-7=-2
2*4=8
3530-80=3450
-
3450
3.4. The first number of a factor is one less than the last number, and the ten numbers of a factor are multiplied by two numbers whose sum is equal to 9.
Method: Add 1 to the first place of 9, and then multiply it by the first place's complement, and the number obtained is the front product. Multiply the complement of the mantissa of the first digit less than the mantissa by the number of 9 and add 1 to the back product. No ten digits complement 0.
For example: 56×36
10-6=4
3+ 1=4
5*4=20
4*4= 16
-
20 16
3.5. Two digits of different numbers in two factors are multiplied, and the tails are complementary.
Method: Determine multiplier and multiplicand, and vice versa. Multiply the multiplier head by one, the number is the front product, the tail is multiplied by the tail, and the number is the back product. Let's see if the head of the multiplicand is bigger or smaller than the head of the multiplier. If it is large, add the tails of several multipliers and multiply by ten, and vice versa.
For example: 74×56
(7+ 1)*5=40
4*6=24
7-5=2
2*6= 12
12* 10= 120
4024+ 120=4 144
-
4 144
3.6, two-factor head-tail difference one, mantissa complementary algorithm.
Method: Don't bother with the fifth one. The number obtained by subtracting one from the first square of a large number is the front product, and the hundred after rounding the tail square of a large number is the back product.
For example: 24×36
3 & gt2
3*3- 1=8
6^2=36
100-36=64
-
864
3.7. Two-digit algorithm close to 100
Method: Determine multiplier and multiplicand, and vice versa. The multiplicand subtracts the multiplier's complement to get the front product, and then multiplies the two complements to get the back product (if it is less than 10, it is filled with 0, if it is full, it is 1).
For example: 93×9 1
100-9 1=9
93-9=84
100-93=7
7*9=63
-
8463
B, square fast calculation
Find the square of 1 1 ~ 19 first.
Ibid.: 1.2. When the number of digits of the multiplier is added to the multiplicand, the number is the front product. When the digits of two numbers are multiplied, this number is the post product, full 10, the first one.
For example: 17 × 17
17 + 7 = 24-
7 × 7 = 49
-
289
3. The unit is the square of two digits of 5.
Ibid., 1.3, ten digits plus 1 multiplied by ten digits, followed by 25.
For example: 35 × 35
(3 + 1)× 3 = 12 -
25
-
1225
Four digits or ten digits are the square of five digits.
Same as above, 2.5, one digit plus 25, followed by the square of one digit.
For example: 53 ×53
25 + 3 = 28 -
3× 3 = 9
-
2809
4. Square of 2 1 ~ 50 digits
When finding the square of two numbers between 25 and 50, simply remember the square of 1~25,1~19 refer to the first article. You should remember the following four data:
2 1 × 2 1 = 44 1
22 × 22 = 484
23 × 23 = 529
24 × 24 = 576
Find the square of two digits from 25 to 50, subtract 25 from the radix, the number is the front product, and the square of the difference obtained by subtracting the radix from 50 is the back product, which is full of 1, and there is no ten digits to make up 0.
For example: 37 × 37
37 - 25 = 12 -
(50 - 37)^2 = 169
-
1369
C. addition and subtraction
First, the concept and application of complement
The concept of complement: Complement refers to the number left after subtracting a certain number from 10, 100 and 1000. ...
For example, if 10 minus 9 equals 1, then the complement of 9 is 1, and vice versa.
Application of Complement: Complement is often used in fast calculation. For example, find the multiplication or division of two numbers close to 100, and turn the seemingly complicated subtraction operation into a simple addition operation.
D, quickly calculate the division
I When a number is divided by 5,25, 125.
1, dividend ÷ 5
= dividend ÷ (10 ÷ 2)
= dividend10× 2
= dividend × 2 ÷ 10
2. Dividends ÷ 25
= dividend × 4 ÷ 100
= dividend × 2 × 2 ÷ 100
3. Dividends125
= dividend × 8 ÷ 1000
= dividend × 2× 2 ÷1000
In addition, subtraction, multiplication and division, division is the most troublesome. Even if the speed algorithm is used, it is often necessary to add pen calculation to work out the answer faster and more accurately. Because of my limited level, the above algorithm is not necessarily the best heart algorithm.
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5. Fast Calculation 5: Fast Calculation of Historical Harvest
Quick calculation five: quick calculation of historical gains
The quick calculation method invented by Shi Fengshou, a master of quick calculation, has been studied for 10 years, which is a method of calculating directly with the brain, also called quick mental arithmetic, quick mental arithmetic. This method breaks the traditional method of counting from the low position for thousands of years, and summarizes 26 formulas by using the carry rule. Counting from the high position and counting with the help of fingers can speed up the calculation, which can instantly calculate the correct results, help human beings develop their brain power and strengthen their ability to think, analyze, judge and solve problems. It is a great pioneering work of contemporary applied mathematics.
This set of calculation method, officially named "Fast Algorithm of Historical Harvest" by the state in 1990, has been incorporated into the mathematics textbook of modern primary schools in China's nine-year compulsory education. UNESCO praised it as a miracle in the history of educational science and should be popularized all over the world.
The main functions of the historical harvest speed algorithm are as follows:
From high position, from left to right
No computing tools.
Column-free computing program
⊙ See the formula directly quoting the correct answer.
It can be used for addition, subtraction, multiplication and division of multi-bit data, as well as mathematical operations such as multiplication, square root, trigonometric function and logarithm.
An example of fast calculation method
Examples of fast calculation in practice
○ The stone harvest speed algorithm is easy to learn and use. The algorithm starts from the high position and remembers 26 formulas summarized by the professor of history (these formulas are scientific and interrelated, and need not be memorized) to represent the carry rule of multiplying one digit by multiple digits. If you master these formulas and some specific rules, you can quickly perform operations such as addition, subtraction, multiplication, division, multiplication, root, fraction, function and logarithm.
□ This article illustrates multiplication with examples.
○ Fast algorithm, like traditional multiplication, needs to process every bit of the multiplier bit by bit. We call the number being processed in the multiplicand "standard", and the number from the first digit to the last digit on the right side of the standard is called "last digit". After the standard is multiplied, only the single digit of the product is taken as "this bit", and the number to be carried after the standard is multiplied by the multiplier is "the last bit".
○ The number of digits of the product is the number of digits of the sum of "this addition and last addition", that is-
□ Single digit of total standard = (last ten digits)
○ Then when we calculate, we should find the root and reciprocal bit by bit from left to right, and then add them to get their single digits. Now, let's give a correct example to illustrate the thinking activity in calculus.
(Example) Fill in 0 before the first digit of the multiplicand and list the formula:
7536×2= 15072
The carry rule of multiplier 2 is "2 full 5 decimal 1"
7×2 original 4, later 5, full 50% 1, 4+ 1 get 5.
5×2 is 0, and if the last digit 3 is not input, it is 0.
3×2 is a 6 and the last digit is 6. When 5 is full, enter 1, 6+ 1 and get 7.
6×2 This is a 2, and there is no postposition, so you get 2.
Here are only the simplest examples for readers' reference. As for multiplication 3, 4 ... to multiplication 9, there are certain carry rules. Limited to space, I can't list them all.
Based on these carry rules, a "historical harvest fast algorithm" is gradually developed. As long as it is skillfully used, the purpose of calculating four multi-digit operations quickly and accurately can be achieved.
& gt& gt exercise example 2
□ Mastering the know-how The human brain is better than the computer.
The speed algorithm of stone harvest is not complicated, but it is easier to learn, faster and more accurate than the traditional calculation method. Professor Shi Fengshou said that ordinary people can master the tricks as long as they study hard for one month.
For accountants, businessmen and scientists, fast algorithms can improve the calculation speed and work efficiency; For students, it can develop their intelligence, use their brains flexibly, and help improve their math and physics abilities.
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6, quick calculation 6: Jinhua whole brain quick calculation
Jinhua Whole Brain Fast Computing is a fast brain computing technology course developed by simulating computer operation programs, which allows children to quickly learn to add, subtract, multiply, divide, multiply and look up any number. So as to quickly improve the operation speed and accuracy of children.
The operation principle of Jinhua whole brain quick calculation;
The operation principle of Jinhua whole brain quick calculation is to stimulate the brain through the activities of both hands, so that the brain can directly produce sensitive conditioned reflex to numbers, so the purpose of quick calculation can be achieved.
(1) With the hand as the operator, an intuitive operation process is generated.
(2) As a memory, the brain can react quickly and express the operation process.
For example: 6752+ 1629 =? example
Operation process and method: the first bit 6+ 1 is 7, the last bit (7+6) exceeds 10, carry 1, the first bit 7+ 1 write 8, 100 minus 6' s complement 4 to write 3, (.
Some principles of Jinhua whole brain fast multiplication;
Let a, b, c and d be undetermined numbers, then the product of any two factors can be expressed as:
AB×CD=(AB+A×D/C)×C0+B×D
= AB×C0 +A×D×C0/C+B×D
= AB×C0 +A×D× 10+B×D
= AB×C0 +A0×D+B×D
= AB×C0 +(A0+B)×D
= AB×C0 +AB×D
= AB×(C0 +D)
= AB×CD
This method is more suitable for the multiplication in which c is divisible by A×D, especially for the factors in which two "primes" are integer multiples or one "mantissa" is integer multiples of the "primes".
As long as the first number of two factors is an integer multiple, the product of two factors can be calculated in this way.
That is, when A =nC, AB× CD = (AB+ND )× C0+B× D.
For example:
23× 13=29× 10+3×3=299
33× 12=39× 10+3×2=396