1. mental arithmetic of addition, division and integer addition, for example: 8+5= 13, divide 5 by 2 and 3 first, then it is 8+2+3= 13.

2. Subtract it from an integer, for example, 26+ 18=44, and replace 18 with a tuning block 20-2, so it is 26+20-2=44.

3. Addition of dislocation numbers, for example, one digit plus ten digits is one digit, and 5 1+ 15=66, so that 5+ 1 gets 6, and 1+5 gets 6,26.

4. For example, the number of ten-digit plus eighteen-digit fields is 78+87= 165, so it is 7+8= 15, then add the two numbers of 15 to get 6, and then put this 6 in the middle of 15 to get 65438+.

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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 add, subtract, multiply and divide multiple digits, and can write answers directly without vertical columns.

Quick mental arithmetic is different from abacus mental arithmetic and palm mental arithmetic. The fast mental arithmetic invented by Niu Hongwei, a teacher in Xi 'an, mainly trains children to do addition, subtraction, multiplication and division quickly through certain rules in textbooks.

"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.