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Second, multiple choice questions

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Third, calculation

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Fourth, answer questions.

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This part of the extended materials mainly examines the knowledge points of algebra:

Formulas obtained by finite algebraic operations such as addition, subtraction, multiplication, division, multiplication and square root of numbers and letters representing numbers or mathematical expressions containing letters are called algebraic expressions. For example: ax+2b, -2/3, b 2/26, √a+√2, etc.

Rational expressions include algebraic expressions (rational expressions without letters in divisor) and fractional formulas (rational expressions with letters in divisor and divisor not being 0). In this algebraic expression, only a limited number of operations such as addition, subtraction, multiplication, division and integer idempotency are performed on letters. Algebraic expressions include monomials (numbers or letters, or products of single numbers or letters) and polynomials (sums of several monomials).

When two letters are multiplied, numbers are multiplied by letters, letters are multiplied by brackets, and brackets are multiplied by brackets, the multiplication sign can be omitted. For example, "the product of x and y" can be written as "xy"; "The product of a and 2" should be written as "2a" and "twice the sum of m and n" should be written as "2(m+n)".

When letters are multiplied by numbers or numbers are multiplied by brackets, the multiplication sign can be omitted, but the numbers must be written first. For example, "x×2" should be written as "2x" instead of "x2"; "The perimeter of a rectangle with length and width of A and B respectively" should be written as "2(a+b)" instead of "(a+b)2".