Refers to the use of special relationships between numbers to perform faster addition, subtraction, multiplication and division operations. This method of calculation is called quick algorithm or mental algorithm.
1 Quick Arithmetic One: Quick Mental Arithmetic, Quick Calculation
Quick Arithmetic One: Quick Mental Arithmetic-----A teaching model that is truly synchronized with primary school mathematics textbooks
Quick Mental Arithmetic It is currently the only method to perform simple calculations without using any physical objects. There is no need to practice abacus, fingers, or abacus.
The layout and difficulty of the quick mental arithmetic teaching materials closely follow the elementary school mathematics syllabus and are in line with junior high school algebra, making it a simpler quick mental arithmetic course than elementary school textbooks. Simplified written calculations and strengthened oral calculations. Simple, easy to learn, and highly interesting. After a short period of training, primary school students can add, subtract, multiply, and divide multi-digit numbers without using vertical expressions, and can directly write answers.
The unique effect of fast mental arithmetic
All multi-digit multiplication, division, addition and subtraction for third grade students and above have been learned.
Multi-digit addition and subtraction for second grade students, Two-digit multiplication and one-digit division.
First grade, multi-digit addition and subtraction.
In kindergarten, large classes learn multi-digit addition and subtraction for preschoolers Tailor-made for young children, they can overcome the oral arithmetic level in primary school in advance. Children learning fast mental arithmetic in kindergarten will be helpful in elementary school in the future
Children no longer use scratch paper when doing homework, they just write the answers directly after looking at the calculation.
"Quick mental arithmetic" is different from "abacus" Mental arithmetic" and "hand-brain arithmetic". Fast mental arithmetic invented by Xi'an teacher Niu Hongwei. (Teacher Niu Hongwei obtained a patent certificate issued by the People's Republic of China and the State Intellectual Property Office. Patent number; ZL2008301174275. Inspired by the People's Republic of China and the State Intellectual Property Office. Patent protection under the National Patent Law.) Mainly through certain rules in the teaching materials, "quick mental arithmetic" helps to improve the orderliness, logic and sensitivity of children's thinking and behavior, and train them. Children's eyes, hands, and brain respond quickly and synchronously, and the calculation method is consistent with primary and secondary school mathematics, so it is very popular with parents of young children.
A teaching model that is truly synchronized with primary school mathematics textbooks:
p>
1: Ability to learn arithmetic - written arithmetic training. Today, our country’s education system is exam-oriented education, and the standard for testing students is test scores. Then the students’ main tasks are to take exams, answer questions, and answer questions in writing, and write arithmetic training. It is the main line of teaching. It is consistent with the calculation method of primary school mathematics. It does not use any physical calculations. It can be used freely in both horizontal and vertical calculations. Calculating with a pen is a golden key to starting the smart train.
2: Understand the math and play with math. Being able to write problems with a pen not only helps children learn arithmetic, but also helps them understand the math and make breakthroughs in math and play. Calculation of numbers. Children complete calculations on the basis of understanding.
3: Speed ??training - it is not enough to be able to use pen to calculate problems. Oral calculations in primary schools must be time-limited to ensure that they are up to standard. Time speaks for itself, that is, being able to do math is not enough, the main thing is to speed up.
4: Enlighten wisdom - intellectual gymnastics, not just learning calculations, but focusing on cultivating children's mathematical thinking ability and stimulating them comprehensively. The potential of left and right brains develops the whole brain. After training in fast mental arithmetic, preschool children can deeply understand the essence of mathematics (inclusion), the meaning of numbers (cardinality, ordinal numbers, and inclusion), and the operation mechanism of numbers (addition of numbers with the same digit). Subtraction,) mathematical logic operations enable children to master the decomposition of complex information, and develop divergent thinking and reverse thinking.
2. Quick calculation two: swallow gold in your sleeves. Quick Calculation
Quick Calculation 2: In the popular CCTV drama "Walking to the West Exit", Douhua repeatedly praised Tian Qinghui for his "quick calculation" (that is, calculation without the help of an abacus)! So what exactly is "quick calculation"? Algorithm?
Swallowing gold in the sleeves is a quick calculation method. It is a numerical calculation method invented by ancient Chinese businessmen. The sleeves of ancient people's clothes were fat, and only two hands were used in the sleeves when calculating. It was called Swallowing gold in one's sleeves makes quick calculations. There was a song about this calculation method in the past: "Swallowing gold in one's sleeves is as wonderful as a fairy, and you can count everything with just a flick of your finger. You can learn priceless treasures, and you won't pass them on until you meet a close friend."
He hid his hands in his sleeves for fear of revealing his financial secrets. In the past, people would not easily pass on the secrets of this algorithm in order to make a living. A quick calculation method called "swallowing gold in one's sleeve" that has been circulated in China for at least 400 years is also on the verge of being lost.
According to relevant information, in 1573 AD, a scholar named Xu Xinlu wrote a book "The Bead Plate Algorithm", which was the first to describe the quick calculation of swallowing gold in one's sleeves; in 1592 AD, a scholar named Cheng Dawei, a mathematician, published a book "Algorithmic Coordination", which for the first time gave a detailed description of pocket money. Later, merchants, especially Shanxi merchants, popularized and used this ancient quick calculation method. The "swallowing gold in one's sleeve" algorithm is a secret skill of Shanxi bank accounts. Some big merchants and shopkeepers in Xi'an know this fast algorithm.
. The upper, middle and lower sections of each finger represent numbers 1-9 respectively. There are three numbers arranged on each section. The arrangement rules are divided into three columns: left, middle and right. The left side of the finger is arranged in reverse order (from bottom to top) 1, 2, 3; the middle finger is arranged in downward direction (from top to bottom). 4, 5, 6: Arrange the fingers 7, 8, 9 upside down on the right side. The calculation method of Sodetsu Tonjin is to use mental arithmetic to reproduce the finger arithmetic calculation process using the brain image to obtain the result. It treats the left hand as a five-speed virtual abacus, and uses the five fingers of the right hand to click on the virtual abacus to perform calculations. When counting, use the fingers of your right hand to point to the corresponding fingers of your left hand. The clear division of labor is: the right thumb/left thumb, the right index finger specifically for the left index finger, the right middle finger for the left middle finger, the right ring finger for the left ring finger, and the right little finger for the left little finger. Corresponding professional division of labor does not interfere with each other. Whichever finger is used to count will be extended. If the finger is not used to count, it will be bent to indicate 0. It does not rely on any calculation tools and does not include calculation procedures. It only needs to gently close the hands to know the number. It can perform the four arithmetic operations of addition, subtraction, multiplication and division of any number within 100,000 digits.
. Although for beginners, calculating simple data with 'Sleeve Gold' is not as fast as a calculator, once you master this skill, the calculation speed will be faster than that of a calculator. Someone once specifically calculated the speed of the 'sleeve gold swallowing' algorithm. A person who is proficient in this skill can find that the result is a multiplication of 3 to 4 digits, which takes about 2 seconds; the result is 5 to 7 digits. , about 7 seconds;
Although the Xiuli Tunjin Speed ??Algorithm is derived from the abacus, compared with the abacus, it does not require any tools, just one pair of hands. Since "Swallowing Gold in Sleeves" does not require tools or eyesight, it is very suitable for use in field operations and can also be used in the dark, especially for blind people, who can use this algorithm to solve some problems. "As the saying goes, 'Ten fingers connect to the heart', using fingers to train calculation skills can move the muscles and bones, make the mind dexterous, and dexterity stimulates the soul and improves brain power."
Nowadays, businessmen don't have to settle accounts with quick algorithms. . However, some educators have applied this method to the field of early childhood education. Teacher Niu Hongwei from Xi'an has been engaged in education for many years and has made improvements to Tunjin in the Sleeve. Make it easier to learn, convenient and fast. He has taught thousands of children to learn the improved "swallowing gold in one's sleeves" method. It has a good effect in stimulating children's intelligence. Have money in your pocket - develop your child's whole brain. Swallowing gold in one's sleeves is not a special function, but a scientific teaching method. It is more magical than abacus mental arithmetic. It uses the hands and brain to complete fast calculations of addition, subtraction, multiplication and division, with amazing speed and high accuracy. It effectively develops students' brains and stimulates students' potential. The innovative sleeve-swallowing quick calculation------whole-brain and hand-mental arithmetic---was awarded the patent certificate issued by the State Intellectual Property Office of the People's Republic of China and the People's Republic of China on May 6, 2009 by Mr. Niu Hongwei. Patent number; ZL2008301164377. It is protected by the Patent Law of the People's Republic of China.
The Xiulitonjinsu algorithm reduces the complex calculation process of written calculations, saves time and effort, and improves students' calculation speed.
Able to calculate addition, subtraction, multiplication and division of any number within 100,000 digits. Use your hands and brain to quickly complete addition, subtraction, multiplication and division calculations with high accuracy. After two or three months of learning, the lower grade children can blurt out the answers to calculations like 64983+68496 and 78×63 by putting their hands together.
Innovative in-sleeve gold speed algorithm---whole-brain mental arithmetic is a method for children to record in their hands and calculate in their brains. It does not use any calculation tools, does not use vertical formulas, and just puts the hands together to know. Answer. This method is: use the left hand's joint strips to simulate the bead positions on the abacus for counting, use the left hand as a "five-position small abacus" and use the right hand to pull out the beads for calculation, so that the human hands become a perfect calculation device. Students can calculate results of hundreds of thousands of digits during the calculation process. It is easy to understand and learn, and can truly train children's brain, heart, and hands, and improve children's computing power, memory, and self-confidence.
3 Quick Calculation Three: Montessori Quick Calculation
Quick Calculation Three: Montessori Quick Calculation is a development and innovation based on Montessori mathematics. "Speed ??Calculation" is aimed at children in preschool. The biggest advantage is that it has good connection with early childhood and is consistent with the mathematical calculation methods of primary schools. It is suitable for children in kindergarten, middle class and upper class and first and second grade students in primary school.
Montessori Quick Calculation enables children to deeply understand the fundamental principles of numerical calculations while playing. This makes it easy to break through children's mathematical calculation skills. The calculation of numbers contains abstract thinking such as inclusion, classification, decomposition and merging, induction, symmetrical logical reasoning, etc. However, preschool children can only think in images and cannot understand and reason, so preschool children learn to calculate. is very difficult. The birth of Montessori Quick Calculation Cards enables the principles of mathematical calculations to be displayed in front of children in the form of images. Once a child understands arithmetic, calculation will naturally become easier. When you put two numbers 5 and 6 together, not only the answer is displayed, but also why the carry is needed. This is the latest invention patent of Mr. Niu Hongwei from Xi'an, Montessori Quick Calculation (Patent No.: ZL2008301164396). One of its cards contains The number's writing method, number's shape, number's quantity (base) and number contain 4 pieces of information. This way you can easily lead your children into the interesting digital kingdom.
Montessori Quick Calculation - Simple calculation, fully in line with the national nine-year compulsory education curriculum standards, so that 4.5-year-old children can learn addition and subtraction operations within 10,000 in one semester. Montessori Speed ??calculations start from the most basic number concepts and link them step by step, which is consistent with the calculation methods of primary school mathematics. But the teaching method is simple, easy for students to learn and accept. Montessori Quick Calculation is a relaxed and happy teaching, using digital images such as cartoons and real objects to visualize abstract and boring mathematical concepts and simplify complex problems. Montessori speed calculation is a new way to connect the best mathematics courses in early childhood and improve children's mathematics quality.
4 Quick Calculation Four: Quick Calculation of Special Numbers
Quick Calculation Four: Quick Calculation of Conditional Special Numbers
Quick Calculation Skills for Two-Digit Multiplication
< p> Principle: Suppose the two digits are 10A+B and 10C+D respectively, and their product is S. Expand according to the polynomial:S= (10A+B) × (10C+D)=10A× 10C+ B×10C+10A×D+ B×D, and the so-called quick calculation is to simplify the above formula based on some of the relationships that are equal or complementary (adding to ten), so as to quickly get the result.
Note: "--" below represents the tens and ones digits, because the number obtained by multiplying the tens digits of two digits is followed by two zeros. Please don't forget that the pre-product is the pre- For two digits, the back product is the last two digits, and the middle product is the middle two digits. The first one is the first one if it reaches ten, and zero is added if it is insufficient.
A. Quick calculation of multiplication
1. The first digit is the same:
1.1. The tens digit is 1, and the ones digit is complementary, that is, A=C=1, B+D=10, S=(1B+D)×1A× B
Method: The hundreds digit is two, the ones digit is multiplied, the resulting number is the back product, and the first one is the first one when it reaches ten.
Example: 13×17
13 + 7 = 2- - ("-" is used as a mnemonic when you are not familiar with it, but you can no longer use it after you are familiar with it)
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3 × 7 = 21
-----------------------
221
That is, 13×17= 221
1.2. The tens digit is 1, and the ones digit is not complementary, that is, A=C=1, B+D≠10, S=(1B+ D) × 10 + A × B
Method: Add the ones digit of the multiplier and the multiplicand, and the number obtained is the front product. Top ten.
Example: 15×17
15 + 7 = 22- (“-” is used as a mnemonic when you are not familiar with it, and you don’t need to use it after you are familiar with it)
5 × 7 = 35
-----------------------
255
That is 15×17 = 255
1.3. The tens digit is the same and the ones digit is complementary, that is, A=C, B+D=10, S=A×(A+1)×1 A×B
Method: Add 1 to the tens digit, multiply the sum by the tens digit, and the result is the pre-product. Multiply the single digits, and the result is the back product
Example: 56 × 54
(5 + 1) × 5 = 30- -
6 × 4 = 24
----- ------------------
3024
1.4. The tens digits are the same, but the ones digits are not complementary, that is, A=C,B+ D≠10,S=A×(A+1)×1A×B
Method: add one to the first and then multiply the first two, the number is the front product, multiply the tail by the tail, the number is the back product , add up the multipliers to see how many are greater or less than ten. If it is greater, add the first few multipliers and multiply them by ten, and vice versa
Example: 67 × 64
(6+1)×6=42
7×4=28
7+4=11
11-10=1
< p> 4228+60=4288-----------------------
4288
Method 2: Multiply the two first digits (that is, find the square of the first digit), and the resulting number is used as the front product. The sum of the two mantissas is multiplied by the first digit, and the resulting number is used as the middle product. If the number reaches ten, multiply the two mantissas and the resulting number is Back accumulation.
Example: 67 × 64
6 × 6 = 36- -
(4 + 7) × 6 = 66 -
4 × 7 = 28
-----------------------
4288
Two , with the same last digit:
2.1. The ones digit is 1, and the tens digit is complementary, that is, B=D=1, A+C=10 S=10A×10C+101
Method : The tens place is multiplied by the tens place, and the result is the preproduct, plus 101.
- -8 × 2 = 16- -
101
------------------- ----
1701
2.2.
Method: The product of tens digits, plus the sum of tens digits is the pre-product, and the units digit is 1.
Example: 71 × 91
70 × 90 = 63 - -
70 + 90 = 16 -
1
----------------------
6461
2.3 The ones digit is 5, and the tens digit is complementary That is, B=D=5, A+C=10 S=10A×10C+25
Method: Take the product of ten digits, add the sum of ten digits to the pre-product, and add 25.
Example: 35 × 75
3 × 7+ 5 = 26- -
25
------- ---------------
2625
2.4
Method: Multiply the two first digits (that is, find the square of the first digit), and get the number as the preproduct, the sum of the two tens digits and the ones digit Multiply the two numbers together, and the resulting number will be used as the middle product. If the number reaches ten, add one to one. Multiply the two mantissas and the resulting number will be used as the back product.
Example: 75 ×95
7 × 9 = 63 - -
(7+ 9) × 5= 80 -
25
----------------------------
7125
2.5. The ones digit is the same, and the tens digit is complementary, that is, B=D, A+C=10 S=10A×10C+B10B2
Method: Multiply the tens digit and the tens digit and add the ones digit, The resulting number is the preproduct, plus the square of the ones place.
Example: 86 × 26
8 × 2+6 = 22- -
36
------- ----------------
2236
2.6. The ones digit is the same, but the tens digit is non-complementary
Method: Multiply the tens digit by the tens digit and add the ones digit, and the result is the preproduct. Add the square of the ones digit, and then see how much larger or smaller the sum of the tens digits is than 10. If it is larger, add a few units digits and multiply by ten. Vice versa
Example: 73×43
7×4+3=31
9
7+4= 11
3109 +30=3139
-----------------------
< /p>
Example: 73×43
7×4=28
9
2809+(7+4)×3×10= 2809+11×30=2809+330=3139
-----------------------
3139< /p>
3. Special types:
3.1. One factor has the same first and last numbers, and one factor multiplies two-digit numbers with complementary tens and units digits.
Method: Add 1 to the first digit of the complementary number, multiply the resulting sum by the first digit of the multiplicand, and the resulting number is the pre-product. Multiply the two mantissas, and the resulting number is the post-product. There is no tens digit. 0 complement.
Example: 66 × 37
(3 + 1) × 6 = 24- -
6 × 7 = 42
- ---------------------
2442
3.2. The first and last numbers of a factor are the same. The tens of digits of a factor are the same as Multiply non-complementary two-digit numbers in the ones digit.
Method: Add 1 to the first digit of the messy number, multiply the resulting sum by the first digit of the multiplicand, and the resulting number is the pre-product. Multiply the two mantissas, and the resulting number is the post-product. There is no tens digit. 0's complement, let's look at how many non-complementary factors add up to 10. If it's larger or smaller, add a few numbers of the same number to multiply by ten, and vice versa
Example: 38×44
(3+1)*4=12
8*4=32
1632
3+8=11
11-10=1
1632+40=1672
-----------------------< /p>
1672
3.3. A factor number is complementary from beginning to end, and a factor multiplies two-digit numbers with different tens and units digits.
Method: Add 1 to the first digit of the multiplier, multiply the resulting sum by the first digit of the multiplicand, and the resulting number is the pre-product. Multiply the two mantissas, and the resulting number is the post-product. If there are no tens, add 0 , then look at how many different factors have the tail larger or smaller than the first. If it is larger, add the first of several complementary numbers multiplied by ten, and vice versa
Example: 46×75
< p> (4+1)*7=356*5=30
5-7=-2
2*4=8
3530-80=3450
-----------------------
3450
3.4. The leading number of a factor is one less than the tail. The sum of the tens and units digits of a factor equals 9 multiplied by a two-digit number.
Method: Add 1 to the first digit of the number that makes up 9 and multiply it by the complement of the first number. The resulting number is the pre-product. The complement of the mantissa of the number whose first number is one less than the last number is multiplied by the first digit of the number that makes up 9. 1 is the back product, and there are no tens digits to be filled with 0.
Example: 56×36
10-6=4
3+1=4
5*4=20
p>4*4=16
---------------
2016
3.5, two Two-digit numbers with different starting numbers and complementary tails are multiplied.
Method: Determine the multiplier and multiplicand and vice versa. Add one to the first part of the multiplicand and multiply it by one to the first part of the multiplier, and the number obtained is the front product. Multiply the tail by the tail, and the number obtained is the back product. Let’s see how much larger or smaller the head of the multiplicand is than the head of the multiplier. If it’s larger, add the tails of several multipliers multiplied by ten, and vice versa
Example: 74×56
(7+1)*5=40
4*6=24
7-5=2
2*6=12< /p>
12*10=120
4024+120=4144
---------------
< p> 41443.6. Algorithm for two factors whose first and last differences are one, and whose mantissas are complementary
Method: Don’t bother with the fifth one, just take the square of the larger first and subtract one to get the number is the front product, and the completed hundred of the tail square of a large number is the back product
Example: 24×36
3>2
3*3- 1=8
6^2=36
100-36=64
---------------< /p>
864
3.7. Two-digit algorithm for nearly 100
Method: Determine the multiplier and multiplicand, and vice versa.
Then subtract the complement of the multiplier from the multiplicand, and the number obtained is the front product. Then multiply the complements of the two numbers together, and the number obtained is the back product (fill in zeros if it is less than 10, and round up one if it is over 100)
Example: 93×91
100-91=9
93-9=84
100-93=7
7 *9=63
---------------
8463
B. Quick square calculation
< p> 1. Find the squares of 11 to 19Same as 1.2 above. Add the ones digit of the multiplier and the multiplicand, and the result is the preproduct. Multiply the ones digits of the two numbers, and the result is the post product. Accumulate, the first one up to ten
Example: 17 × 17
17 + 7 = 24-
7 × 7 = 49
---------------
289
3. The ones digit is the square of the two-digit number 5
Same as above 1.3, add 1 to the tens place, multiply by the tens place, and add 25 after the result.
Example: 35 × 35
(3 + 1) × 3 = 12--
25
----- ------------------
1225
The fourth and tens digits are the two-digit squares of 5
Same as 2.5, add 25 to the ones digit, and add the square of the ones digit after the number.
Example: 53 × 53
25 + 3 = 28--
3× 3 = 9
----- ------------------
2809
4. Squares of two-digit numbers from 21 to 50
When finding the square of two numbers between 25 and 50, it is simple to remember the square of 1 to 25. For 11 to 19, refer to the first item. The following four data should be remembered:
21 × 21 = 441
22 × 22 = 484
23 × 23 = 529
24 × 24 = 576
Find two pairs of 25 to 50 For the square of a digit, subtract 25 from the base, and the resulting number is the pre-product. The square of the difference obtained by subtracting the base from 50 is the back-product. If there is a hundred, 1 is added, and 0 is added if there is no tens.
Example: 37 × 37
37 - 25 = 12--
(50 - 37)^2 = 169
- ----------------------------------
1369
C. Addition and subtraction Method
1. The concept and application of complements
The concept of complement: complement refers to what is left after subtracting a certain number from 10, 100, 1000... number.
For example, 10 minus 9 equals 1, so the complement of 9 is 1, and conversely, the complement of 1 is 9.
Application of complements: Complements are often used in quick calculation methods. For example, find the multiplication or divisor of two numbers close to 100, convert seemingly complex subtraction operations into simple addition operations, etc.
D. Quick calculation of division
1. When dividing a number by 5, 25, or 125
1. Divisor ÷ 5
= Dividend ÷ (10 ÷ 2)
= Dividend ÷ 10 × 2
= Dividend × 2 ÷ 10
2. Dividend ÷ 25
< p> = dividend × 4 ÷100= dividend × 2 × 2 ÷100
3. Dividend ÷ 125
= dividend × 8 ÷1000
= dividend×2 You can calculate the answer faster and more accurately by doing math in writing. Due to my limited ability, the above algorithm may not be the best mental algorithm
5 quick calculations: Shi Fengshou’s quick calculations
Quick calculations five: Shi Fengshou’s quick calculations
The fast calculation method developed by Shi Fengshou, a master of speed calculation, after 10 years of research, is a method that directly relies on the brain to perform calculations. It is also called fast mental arithmetic and fast brain calculation. This method breaks the traditional method of counting from the lowest position for thousands of years. It uses the carry rule and summarizes 26 formulas. It counts from the highest position and then cooperates with finger calculation to speed up the calculation. It can calculate the correct result in an instant and help humans develop their brain power. , strengthening the ability of thinking, analysis, judgment and problem solving is a major innovation in contemporary applied mathematics.
This set of calculation methods was officially named "Shi Fengshou Speed ??Algorithm" by the country in 1990, and has now been incorporated into the "Modern Primary School Mathematics" textbook for China's nine-year compulsory education. UNESCO hails it as a miracle in the history of educational science and should be promoted to the world.
The main features of the Shifeng harvest speed algorithm are as follows:
⊙ Count from the highest position, from left to right
⊙ No calculation tools are needed
⊙ No calculation program
⊙Report the correct answer directly when you see the calculation
⊙Can be used in addition, subtraction, multiplication and division of multi-digit data, as well as exponentiation, square root, trigonometric functions, and pairs Example of Rapid Calculation in Practice
Example of Rapid Calculation in Practice
○Shi Fengshou’s rapid algorithm is easy to learn and use, and the algorithm starts from high digits To start counting, remember the 26 formulas summarized by Professor Shi (these formulas do not need to be memorized, but are in line with scientific laws and connected with each other) to express the carry rule for multiplying one number by multiple digits, and mastered these formulas. With some specific rules, you can quickly perform operations such as addition, subtraction, multiplication, division, exponentiation, square root, fractions, functions, logarithms, etc.
□This article gives an example of multiplication
○The fast algorithm is the same as traditional multiplication, and each digit of the multiplier needs to be processed bit by bit. We take the multiplicand being processed That digit is called the "base", and the number represented from the first digit to the right of the base to the last digit is called the "last digit". After the basic digit is multiplied, only the single digit of the product is taken, which is the "original one", and the number that needs to be carried after the last digit of the basic digit is multiplied by the multiplier is the "backward".
○Each digit of the product is the single digit of the sum of "the original plus the last ten", that is--
□The basic product = the single digit of the sum of (the original ten). Digits
○Then when we calculate, we need to find the original and backward digits from left to right, then add them up and then take the single digits. Now, let’s use the example on the right to explain in detail the thinking activities during calculation.
(Example) Add 0 to the first digit of the multiplicand and list the formula:
7536×2=15072
The carry rule for a multiplier of 2 is " 2 and 5 go into 1"
7×2 has a 4, and the last digit is 5, and 5 and 1 go into 1, 4+1 gets 5
5×2 has a 0, and the last digit is 5 If 3 does not advance, the result is 0
3×2 has a 6, and the last digit is 6. If 5 is reached, 1 is entered, and 6+1 is 7.
6×2 has a 2, and there is no last digit. bit, get 2
Here we only give the simplest example for readers' reference. As for multiplying by 3, 4... and multiplying by 9, there are also certain carry rules. Due to space limitations, we cannot elaborate here. One list.
"Shi Fengshou Speed ??Algorithm" is gradually developed based on these carry rules. As long as it is used proficiently, all multi-digit operations such as addition, subtraction, multiplication and division can be performed quickly and accurately.
>>Drill Example 2
□ Master the trick and the human brain is better than the computer
The Shifeng harvest speed algorithm is not complicated and is easier to learn and faster than the traditional calculation method , more accurately, Professor Shi Fengshou said that most people can master the tricks as long as they study hard for a month.
For accountants, economic and trade personnel, and scientists, quick algorithm can improve calculation speed and increase work efficiency; for school children, it can develop intelligence, use their brains, and help enhance their mathematical abilities.