1, the addition formula without carry: (Be sure to see that Chu Jin Chu does not carry)

A: Two digits plus one digit: write down ten digits first, and then write down the sum of the digits.

B two digits plus two digits: write the sum of ten digits first, and then write the sum of one digit.

C multi-digit plus multi-digit: write the sum of the numbers on the same digit in turn from the high position?

2、? Carry addition formula (be sure to observe whether to carry)

Quick addition technique? The key of carry addition is to push 1 to a higher number of digits. Since it's a definite thing, can you push 1? After observation, you can start counting from the high position.

A two digits plus one digit: write the sum of ten digits plus 1 first, and then write the single digits of the sum of single digits (using the formula of adding within 20)?

B two digits plus one digit: first write down two digits to make a ten digit after integer ten, and then write down the remaining digits after dividing one digit by one. (that is, separate one digit and round two digits to ten digits)

Quick addition skill 15+8= process: 15+5=20 Write 2, 8 divided by 5, then leave 3, and then write 3. ?

Extended data fast mental arithmetic mode

1. Learning algorithm-written arithmetic training. At present, China's education system 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, clear arithmetic-arithmetic and play. Being able to write questions with a pen not only helps children understand arithmetic, but also helps them understand it. 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 not enough to use the pen to calculate the problem, the primary school's oral calculation must have time limit, whether it meets the standard, it takes time to talk, that is, the problem is not enough, mainly to speed up.

4. Enlighten 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.

Baidu encyclopedia-quick mental arithmetic