how to learn abacus multiplication

There are many kinds of cultural relics abacus. For example, the blue-and-white baby abacus of Jingdezhen kiln in Qing Dynasty was a historical relic. Its blue-and-white color was elegant, the glaze was bright and lustrous, the color of the body was white and yellow, and there were obvious flint red spots. The body was solid and the body was thick. The abacus was rectangular and made in imitation of a wooden abacus. It was 29.7 cm long, 13.9 cm wide, 3 cm thick, and weighed 1702 grams. There were 11 stalls. There were 2 beads on the beam in the middle of the stall (5 beads per stall) and 5 beads under the beam (1 bead per stall). Two beads were broken in a small stall, leaving a total of 75 beads. The inner wall of the abacus was glazed, and the outer wall was decorated with blue-and-white baby play patterns. The image of a child was vivid and lifelike. The counting beads were glazed with white glaze, and the bottom and inside of the abacus were exposed without glaze and rough. Several cracks on the body had been repaired. It provided physical evidence for the study of Jingdezhen blue-and-white porcelain production technology in the Qing Dynasty and traditional China calculation tools. There was also the Diamond Abacus, which was originally the collection of Chen Baoding, a famous collector in Shanghai. Later, it was given to the Abacus Museum in Huangshan City for display. These cultural relics reflected the technological level, cultural value and historical significance of the abacus in different periods. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

Abacus comics usually have unique art styles and interesting storylines that attract readers.

In the anime " Fox Demon Little Matchmaker," Tushan Rongrong was the second in command of Tushan. She was known as the " strongest brain," and had the title of Thousand-faced Fox.  She was in charge of Mud Mountain's financial affairs, and she always had an abacus in her hand. Whenever there was a need to provide services, she would record the accounts. While waiting for the TV series, you can also click on the link below to read the original work of " Little Fox Demon Matchmaker " to understand the plot in advance!

Nine Nine to One was the mnemonic formula for reduction and restoration in the abacus. The abacus's incantation, Nine Nine to One, had specific calculation operations, such as "one up one, one down five to four, one to nine into one, two up two, two down five to three, two to eight into one, three up three, three down five to two, three to seven into one, four up four, four down five to one, four to six into one" and so on. The abacus formula was based on an algorithm invented using counting sticks. It was suitable for the abacus and had a history of more than 2600 years. With the use of the abacus, people summed up these formulas to increase the speed of calculation. Furthermore, the concept of "Nine Nine to One" had evolved from a chant in the abacus to a common saying in life. It referred to returning to the beginning, the original state. 'The Myth of True Love in the Pangu Progenitor Universe' is equally wonderful. Please click to read it!

The following is an all-purpose reflection on the teaching of oral multiplication: ** I. Achievement of teaching objectives ** In the teaching of verbal multiplication, the first thing to consider was whether the students understood the meaning of multiplication in specific situations. For example, when teaching 10, 100, and 1,000 times a single digit number, one should pay attention to whether the student can understand the nature of this operation with reference to life examples. If the students could accurately list the multiplication formula according to the given situation in the classroom, such as seeing that there were 20 apples in each basket and how many there were in three baskets, they could quickly list 20×3, which indicated that there was a certain effect in the teaching of the meaning of multiplication. However, if some students still had a vague understanding of the meaning of multiplication, it might be because they did not have a deep enough understanding of the situation creation or guidance. They needed to strengthen the explanation of examples or increase the interaction to let the students explain the meaning behind the formulas. The mastery of the mental arithmetic method depended on whether the student could explore and use it correctly. In teaching, students should be guided to summarize the methods of mental arithmetic through independent thinking and group communication. For example, multiplying a number by ten, one could first calculate the product of ten digits and one digit, and then add 0 at the end. If most of the students could skillfully use this method to do mental arithmetic, it meant that the guidance of the teaching method was relatively successful. However, if some students had a high calculation error rate, it might be because the explanation of the calculation theory was not thorough enough, and the students did not really understand why the calculation was done in this way. It was necessary to carry out targeted intensive training in the subsequent teaching. ** 2. The effectiveness of teaching methods ** 1. ** Situation Teaching Method ** - [Strengths: Creating life-related scenarios, such as combining verbal multiplication with shopping and distributing items, can increase students 'interest in learning and make it easier for them to understand the meaning of multiplication.] For example, when teaching a hundred times a single digit, create a situation where the supermarket buys a whole box of milk (100 boxes per box, buy 3 boxes), so that students can intuitively feel the practical application of multiplication. - Weakness: If the situation is too complicated or out of touch with the actual life of the student, it may distract the student or make it difficult for the student to understand. For example, in some cases, introducing some unfamiliar business discount situations to explain multiplication might be counterproductive. The method of improvement was to understand the students 'life experiences deeply and choose simple and common situations for teaching. 2. ** Independent Exploration and Cooperation Exchange Method ** - "Strengths: Students are encouraged to explore the method of mental arithmetic multiplication on their own. Then, they can improve and improve it through group cooperation and communication. It helps to cultivate students 'independent thinking ability and cooperative learning ability." For example, when discussing the method of multiplying a whole ten by a whole ten, students could try different calculation ideas and then share them in the group to summarize the effective method together. - [Weakness: In the process of group cooperation, there may be situations where individual students lead the discussion, but some students are not very involved.] This required the teachers to arrange the members reasonably when dividing the groups and to patrol and guide the group activities to ensure that every student could actively participate in the exploration and communication. ** 3. Student learning experience and classroom atmosphere ** 1. ** Learning Experience ** - In the teaching of mental arithmetic multiplication, attention should be paid to whether the students 'learning experience was positive or not. If students showed curiosity and desire to explore new knowledge in class and actively participated in the exploration of mental arithmetic methods, it meant that they had a good experience in the learning process. However, if students showed fear of difficulty or lack of interest in teaching activities, it might be because the difficulty of the teaching content was unreasonable or the teaching method was not novel enough. 2. ** Class atmosphere ** - Creating a positive and active classroom atmosphere was crucial to the teaching of mental arithmetic multiplication. When the classroom was full of interaction, students actively answered questions, and the group discussion was lively, it helped to improve the learning effect of students. On the other hand, if the atmosphere in the classroom was dull, students did not dare to speak or the participation was low, teachers needed to reflect on whether their teaching style was too serious, or whether the teaching process was not attractive enough, so as to adjust the teaching strategy and increase the fun and interaction of the classroom. ** 4. Rationally acceptable teaching content ** 1. ** Difficulty of content ** - The teaching content of mental arithmetic multiplication should be gradual, starting from the simple ten times one digit number, and gradually transition to the more complicated situations such as the whole hundred, the whole thousand times one digit number, and the whole ten times the whole ten. If the content was too simple, the students would feel that it was not challenging and would easily underestimate it. If the content was too difficult, it would make the students feel frustrated. Therefore, the difficulty of the teaching content should be adjusted according to the actual learning situation of the students. 2. ** The content is systematic ** - The systematic nature of the teaching content was also crucial. In the teaching of oral multiplication, one should pay attention to the relationship between knowledge, such as the relationship between the whole ten multiplied by one digit and the table multiplication, the similarities between the calculation methods of the whole hundred multiplied by one digit and the whole ten multiplied by one digit, etc. If the teaching content was not systematic, students might learn each knowledge point in isolation, making it difficult to form a complete knowledge system, affecting their overall mastery of mental arithmetic multiplication. ** 5. Teaching Evaluation and feedback ** 1. ** Evaluation Method ** - In the teaching of mental arithmetic multiplication, the evaluation methods should be varied. In addition to the traditional written test, they could also use classroom questions, group competitions, self-evaluation and mutual evaluation. For example, through classroom questions, students could learn about their knowledge in a timely manner. Group competitions could stimulate students 'sense of competition and teamwork. Students' self-evaluation and mutual evaluation could cultivate their self-reflection ability and critical thinking. 2. ** Use feedback ** - Teachers should pay attention to the use of teaching feedback. Whether it was the students 'answers in class, mistakes in practice, or the completion of homework after class, they were all valuable feedback. If they could analyze this feedback in time, find out the problems of the students and adjust the teaching strategy, they could improve the teaching effect. For example, if many students were found to make more mistakes in the calculation of a hundred times a dozen, they could carry out special review and intensive training for this knowledge point. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

The following is an example of a teaching reflection on the law of multiplication: ** I. Reflection on the overall teaching situation ** The laws of multiplication included the commutativity law, the association law, and the distribution law. In the teaching process, the overall teaching arrangement should follow the students 'cognitive laws and start from the students' existing knowledge base. ** 2. Strengths of Teaching ** 1. ** Knowledge Connection ** - The law of multiplication was usually taught after the law of addition, which provided a good foundation for students to learn the law of multiplication. For example, the commutative law of addition and the commutative law of multiplication had certain similarities. Students could understand the commutative law of multiplication by analogy. This kind of knowledge transfer would help students accept new knowledge content faster. 2. ** Teaching Method Usage ** - Creating life situations (such as sports games, planting trees, etc.) was an effective teaching method when exploring the commutive law and the association law of multiplication. It could stimulate students 'interest in learning, make students more intuitively feel the connection between mathematics and life, and pave the way for the concept of the law of multiplication. - When guiding students to explore the distribution law of multiplication, it was a good choice to introduce practical problems that students were familiar with. Students were allowed to use their existing knowledge to migrate, explore and discover the rules by themselves, and verify the rules through examples. This could cultivate the students 'ability to think and explore independently. 3. ** Cultivating students 'abilities ** - In the teaching process, by letting the students calculate the exercises, divide them into groups to compete for the red flag, and so on, the students could find problems in the calculation, explore the problems, and verify the rules. It was helpful to cultivate the students 'ability to find problems, analyze problems, and solve problems. At the same time, it could also increase the students' participation and let the students understand the law of multiplication more deeply. ** 3. Inadequacies in the teaching process ** 1. ** Concept Division ** - Although it was beneficial to distinguish the two laws when combining them in teaching, some students still did not have a clear distinction between the two laws. This might be due to the lack of in-depth analysis and comparison of the two concepts in the teaching process, which led to students being easily confused in practical application. 2. ** Difficulty Breakthrough ** - The distribution law of multiplication was a difficult point in teaching. For some simple calculations with slight changes, such as 3.8×9.9 and 102×0.45 in the multiplication of decimals, the students had a high error rate. This reflected that in the teaching process, the explanation of the various forms and flexible applications of the multiplication distribution law was not thorough enough, and some students could not draw inferences from one example. 3. ** Student participation ** - There were shortcomings in the group cooperation and exchange learning, and the students 'autonomy and inquiry learning were not fully reflected. It could be that the task allocation was not clear enough, or the teacher's guidance during the group discussion was not timely and effective enough, resulting in some students not fully participating in the group discussion and learning. 4. ** For all students ** - In teaching, due to the large number of students, some students who did not like to speak rarely had the opportunity to express themselves. This showed that the teaching process did not pay enough attention to the needs of all students and did not provide equal opportunities for each student to learn and display. ** IV. Modification measures ** 1. ** Strengthened Concept Teaching ** - In the future, for concepts that were easily confused, such as the commutive law of multiplication and the law of association, the time for comparison teaching should be increased. More examples and exercises should be used to deepen the students 'understanding and distinction of concepts. 2. ** Breakthrough Difficulties ** - In order to deal with the difficulty of the multiplication distribution law, special exercises should be added. From simple to complex, students should be gradually guided to master the various application forms of the multiplication distribution law. For questions that students were prone to making mistakes, they had to analyze and explain in detail to help students understand the solution. 3. ** The optimization team cooperated to learn ** - The tasks and goals of the group cooperation were clearly defined. The division of labor in the group was done in advance to ensure that each student was clear about their role and tasks in the group. In the process of group discussion, teachers should strengthen patrol and guidance, answer students 'questions in a timely manner, and encourage every student to actively participate in the discussion. 4. ** Pay attention to all students ** - Design more interaction sessions to encourage students who don't like to speak to actively participate in classroom interactions. He could use a tiered teaching method, designing questions and exercises of different difficulty according to the students 'learning ability and level, so that each student could improve within their own ability and have the opportunity to show their learning results. Through the reflection of the teaching process of the law of multiplication, the advantages and disadvantages of the teaching were clarified, which provided a direction for the future teaching improvement, so as to better improve the teaching quality and help students to grasp the law of multiplication and its application more deeply. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

There were several ways to achieve inverse voltage multiplication: 1. The input voltage was raised using a transformer, and then converted to a reverse voltage through a rectify circuit. 2. Using a voltage doubler circuit, the voltage was increased by connecting multiple reactors in series. 3. A voltage doubler circuit was used to increase the voltage through a multi-stage rectify and filter. 4. Using a voltage amplifier to amplify the input signal to increase the reverse voltage, the negative feedback method can be used to connect the amplifier circuit to obtain the reverse proportional voltage. In addition, there are also chip TC682IOA, TC682COA inverted voltage multiplying IC chips that can be used in related circuits. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

There are 2 baskets, and each basket has 9 apples. So 2 times 9 is 18 apples in total.

The calculation formula of the diagonal determinator was: D = (-1)^t(n, n -1,1)a1, and its value was the product of n elements on the main diagonal (because the determinator value was equal to the algebraic sum of the products of numbers on different rows and columns, and in the diagonal determinator, only the main diagonal had numbers that were not 0, and the rest of the products had factors of 0, that is, the products were all 0). It could also be calculated by descending the order from the first row. The first time it appeared (-1)^(n + 1), the second time it appeared (-1)^n, the third time it appeared (-1)^(n - 1),…the last time it appeared (-1)^3. The symbol of the coefficient was (-1)^((n + 1)+n+…+3)=(-1)^(((n + 1+3)(n - 1)/2)=(-1)^(n(n - 1)/2). In addition, if the first row and the last row were exchanged, the determinant value would change sign, and then the second row and the penultimate row would be exchanged. If n = 2k (k is an integral number), it would become an ordinary diagonal matrix after k exchanges. If n = 2k - 1, it would become a diagonal matrix after (n - 1)/2 exchanges. Multiplied by-1 with each exchange, so the result is that if n = 2k, the determinant =(-1)^(n/2)s (s equals the product of all negative diagonal elements); if n = 2k - 1, the determinant =(-1)^((n - 1)/2)s (s equals the product of all negative diagonal elements). <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>