The speed algorithm of primary school mathematics The speed algorithm and calculation teaching of primary school mathematics are often associated with "abstract, boring and tasteless". How to make it easy to understand and be loved by students in teaching has always been a problem that many teachers think about. Let's take a look at the elementary school mathematics speed algorithm. Primary school mathematical speed algorithm 1 1, dozens of times and dozens of formulas: head joint, tail to tail, tail to tail. For example: 12× 14=? Solution:/kloc-0 /×1=12+4 = 62× 4 = 812×14 =168 Note: Numbers are multiplied. If two digits are not enough, please use 0. 2. The heads are the same and the tails are complementary (the sum of the tails is equal to 10). Formula: After a head is added with 1, the head is multiplied by the head and the tail is multiplied by the tail. For example: 23×27=? Solution: 2+1= 32× 3 = 63× 7 = 2123× 27 = 621Note: Number multiplication. If two digits are not enough, please use 0. 3. The first multiplier is complementary, and the other multiplier has the same number: after a head is added with 1, the head is multiplied by the head and the tail is multiplied by the tail. For example: 37×44=? Solution: 3+1= 44× 4 =167× 4 = 28 37× 44 =1628 Note: Number multiplication. If two digits are not enough, please use 0. 4, dozens of eleven times dozens of formulas: head joint, head joint, tail to tail. For example: 2 1×4 1=? Solution: 2× 4 = 8 2+4 = 6/kloc-0 /×1=121× 41= 8615,1/kloc-. For example: 1 1×23 125=? Solution: 2+3 = 53+1= 41+2 = 32+5 = 72 and 5 are at the beginning and end of11× 23125 = 254375 respectively. 6. Multiply a dozen by any number: Formula: The first digit of the second multiplier does not move down, the single digit of the first factor is multiplied by each digit after the second factor, plus the next digit, and then falls down. For example: 13×467=? Solution: 13 bit is 33× 4+6 =183× 6+7 = 253× 7 = 213× 467 = 6071Note: When the ten bits are full, it must be 7. Multi-digit multiplication formula: the former factor multiplies each digit of the latter factor one by one, the second factor times 10, the third factor times 100, and so on: 33* 132=? 33 *1= 3333 * 3 = 9933 * 2 = 6699 *10 = 99033 *100 = 330066+990+3300 = 435633 */kloc-0. The formula of increasing difference method: the preceding addend and the following addend are integers, and the following difference example: 1376+98= 1474 Calculation method: 1376+ 100-2. 2. The formula for finding the sum of two digits with reversed digits: the ten digits of a number plus its single digits multiplied by 1 1 equals the sum. Example: 47+74= 12 1 calculation method: (4+7) x11=121. 3. One eye and three lines addition formula: enter 1 in advance, discard 9 in the middle, and discard 10 at last. For example: 472+872= 1344. Primary school mathematics speed algorithm 3 1: knowing algorithm-written arithmetic training. At present, the education system in China 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. Ming arithmetic-arithmetic spelling, will write questions with a pen, not only can let children know the algorithm, but also let children understand arithmetic. 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, the calculation problem is not enough, mainly the speed. 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. 1. Positive and negative addition: The sum of several consecutive numbers can be obtained by the formula of "positive and negative addition". For example, the famous mathematician Gauss (Germany) did the problem of "Sum of Hundred Numbers" when he was a child, which can be calculated as 2. Rounding up clever calculation: using "rounding up method" can often make the calculation easier and faster. Third, identity deformation: it is an important thought and method, and also an important problem-solving skill. Using what we have learned to carry out purposeful mathematical deformation can often solve the problem quickly. 4. Divide numbers into addition and subtraction: In addition and subtraction of fractions, dividing a fraction into two fractions for subtraction or addition makes the implied quantitative relationship clear and offsets some of them, which can often greatly simplify the operation. (1) is divided into two fractions and subtracted. Borrow first and then pay back: "Borrow first and then pay back" is an important idea and skill in solving mathematical problems. 6. Push from small to large: a mathematical thinking method, but also a fast and skillful calculation skill. When we encounter a large number of complicated problems, we can start with a few special situations, study the characteristics of the problems, find out the general rules, and then deduce the results of the problems. Clever trial and error quotient: divisor is the division of two digits, and some clever trial and error quotient methods can be used to improve the calculation speed. 8. The addition and subtraction of the same numerator fraction have the following calculation rules: when two numerator and denominator are added (subtracted), the result is divided by the product of the original denominator, and the product obtained by multiplying the sum of the original denominator by the same numerator is taken as the numerator. Molecules are the same, and the addition and subtraction of two fractions of denominators is prime numbers can also be calculated according to the above rules, but in the end, we need to pay attention to simplifying the numbers into simplified (simplest) fractions.