1. Borrowing method: Borrow the unit of subtraction to one tenth, and then subtract the corresponding number from the minuend. (as shown in the figure below)
2. Complement method: complete the minuend into an easy-to-calculate number, such as 10, that is, add a number to the minuend to make it 10, 100, 1000, etc. And then subtract the minuend from it. (as shown in the figure below)
3. Decomposition method: the subtrahend is decomposed into smaller numbers for calculation. For example, when one number is subtracted, it is divided into two numbers for subtraction. (as shown in the figure below)
4. Inverse subtraction: reverse the order of the subtrahend and the minuend, and then calculate their difference by addition. (as shown in the figure below)
The importance of primary school mathematics;
1. Develop logical thinking ability: Mathematics is a discipline to train logical thinking. Mathematics education in primary schools can help children develop their logical thinking ability and improve their ability to analyze and solve problems.
2. Improve mathematics literacy: Primary school mathematics education is very important for improving children's mathematics literacy, which can help children master basic mathematics knowledge, skills and thinking methods and lay a solid foundation for further study in the future.
3. Cultivate practical ability: Primary school mathematics education also involves many calculation and application problems related to daily life, which is helpful to cultivate children's practical ability in real life, such as calculation ability, measurement ability and problem-solving ability.