In mathematics, the method of dividing a subtrahend into two numbers is that the subtrahend is equal to 10 after subtracting the first number, and then the second number 10 is subtracted to get the final result. Mathematical method is to express the state of things in mathematical language.

, relationship and process, and deduce, calculate and analyze them, so as to form the method of explanation, judgment and prediction of the problem.

Mathematical method is a scientific research method with mathematics as a tool, that is, mathematical language expresses the state, relationship and process of things, and after deduction, operation and analysis, it forms a method of explanation, judgment and prediction. Mathematics is a universal means for human beings to strictly describe the abstract structure and mode of things, and can be applied to any problem in the real world. All mathematical objects are artificially defined in essence. In this sense, mathematics belongs to formal science, not natural science.

The formulas of the ten-level method are "9 to 1", "8 to 2", "7 to 3", "6 to 4" and "5 to 5". The ten-level method is to divide the subtree into two numbers. Subtracting the first number from the subtree is equal to 10, and then subtracting the second number is equal to 10 to get the final result.

The method of leveling ten is also one of the four techniques. The arithmetic of addition and subtraction is: integer: the same digit is aligned, counting from one digit, and when the addition is more than dozens of digits, it advances to a higher digit; If the subtraction is not enough, subtract 1 from the high position. When this number is added to 10, it will decrease. Decimal: decimal point alignment (that is, same digit alignment); Calculate according to the law of integer addition and subtraction; Align the decimal point with the horizontal line in the number and point to the decimal point.

Fraction: the fraction and denominator are added and subtracted, and the denominator remains the same. Only add and subtract the numerator: add and subtract fractions with different denominators, divide the fractions first, and then operate according to the addition and subtraction algorithm of fractions with the same denominator; Quotes that do not result in the simplest score are divided into the simplest scores.