1. Every two places from the unit to the left are a part. If there are decimals, every two digits from the right of the decimal point are used to separate the sections.

4. Find the complete square number not greater than the first number on the left, which is the "quotient";

3. Subtract the quotient from the first part on the left and write their difference in the second part on the right as the first remainder;

4. Multiply the quotient by 20 and try to divide it by the first remainder to get the largest integer as the trial quotient (if this largest integer is greater than or equal to 10, use 9 or 8 as the trial quotient);

5. multiply the quotient by 20, add the quotient, and then multiply the quotient. If the product is less than or equal to the remainder, write the quotient after it as a new quotient; If the product is greater than the remainder, try again by reducing the trial quotient until the product is less than or equal to the remainder.