First of all, we should lay a good foundation: understand the mathematics education objectives of first-year students, and as far as I know, I can skillfully use addition and subtraction within 20. Knowing this, the steps are clear. 1, know Arabic numerals; 2. Understand the decimal system; 3. Understand the meaning of the formula; 4. Know how to carry. All right, that's it. Let's find a software that allows children to practice addition and subtraction in 20 minutes. It is recommended to do 60 questions in three and a half minutes.

Then cultivate the application ability. There is no real mathematics in primary schools, only arithmetic. After laying the foundation of quick calculation, solving practical problems is the key to cultivate children's ability and enhance their interest.