Algebraic expression is a part of rational formula, which can contain four operations: addition, subtraction, multiplication and division, but in algebraic expression, divisor cannot contain letters. Monomial and polynomial are collectively called algebraic expressions.

Algebraic formula is the most basic formula in algebra. Introducing algebraic expressions is a practical need, and it is also the need to learn the following contents (such as fractions, quadratic equations with one variable, etc.). ). On the basis of studying rational number operation, simple algebraic expression, unary linear equation and inequality, the algebraic expression is introduced. In fact, the relevant contents of algebraic expressions have been learned in the sixth grade, but now the contents of algebraic expressions have strengthened their application and increased the background of practical application.

Addition and subtraction of 1. algebraic expressions

2. Multiplication and division of algebraic expressions

The main problems of the four operations of algebraic expressions are:

Four operations of (1) monomial

This kind of questions mostly appear in the form of multiple-choice questions and application questions, which are characterized by examining four operations of a single item.

(2) Operation of monomial and polynomial

This kind of problems mostly appear in the form of solving problems, which are highly skilled and characterized by examining the four operations of monomials and polynomials.

factoring

The difficulty lies in four basic methods of factorization (raising common factor, using formula, grouping decomposition and cross multiplication). Factorization is the reverse deformation of algebraic expression multiplication, and the introduction of factorization should firmly grasp this point. Items with the same letters and indexes are called similar items, and several constant items are also similar items. Parentheses and square brackets begin with "+". Remove the brackets and the preceding "+"sign. What is in brackets will not change the symbol. There is a "-"before the brackets. Remove the brackets and the "-"in front, and change the symbols of everything in brackets.