Methods and skills of fast calculation in primary school mathematics 1. Change the operation order: In the mixed formula with only "+"and "-",you can change the operation order.
2. Calculate a series whose difference is equal to the difference between two adjacent numbers, which is called arithmetic serial number, also called arithmetic series.
3. When the number of arithmetic consecutive numbers is even, their sum is equal to the sum of the first number and the last number multiplied by half of the number.
A quick calculation method of primary school mathematics 1, complement rounding method
For numbers close to integer ten, integer hundred, integer thousand, etc. In the formula, we can make them into integer ten, integer hundred, integer thousand and so on. Adding and subtracting complement makes the calculation simple and convenient.
2. Decomposition method
In some multiplication and division formulas, a certain number can be decomposed into constant deformation, which makes the calculation simple.
3. Benchmark method
Add up several numbers that are all close to a certain number, and this number can be used as a reference number. Then multiply the reference number by the number of added numbers, and add or subtract the difference between each number and the reference number to get the calculation result.
4. Grouping method
Reorganize the operation grouping of formulas so that they can be simplified by using the operation rules, operation properties and some properties of sum, difference, product and quotient.
5. Formula method
To find the sum of arithmetic progression's numbers, we can use the formula "(the first item+the last item) × the number of items ÷2= sum".
6. Split method
According to the characteristics of numbers, the numbers in the original problem are divided, and then simple calculations are made by using the operation rules and operation properties.
Second, the method of cultivating fast computing ability
1, practice the basic skills of quick calculation-oral calculation
Oral calculation is the basis of quick calculation and the guarantee of the correct rate of quick calculation. When practicing oral calculation, we should not simply pursue speed, but make clear the algorithm, so as to effectively master the basic methods of oral calculation and lay a solid foundation for rapid calculation.
2. Master the law of quick calculation.
The law of quick calculation is the theoretical basis of quick calculation. To learn fast calculation well, we must master the formulas, rules and laws related to fast calculation. When remembering these laws, we should also understand their characteristics.