1, alphanumeric

In mathematics, numbers can be represented by letters. For example, the average weight of a child aged 10 is one kilogram, and the weight of an adult is twice that of a child, so the weight of an adult can be expressed as two kilograms. Usually in formulas containing letters, the multiplication sign can be written as "…", or it can be omitted, such as 2a or 2 a above, and the numbers are usually written before the letters. The operation symbols in addition, subtraction, multiplication and division cannot be omitted.

2. Use letters to represent the algorithm.

Additive commutative law a+b=b+a

The multiplication and distribution law a×(b+c)=a×b+a×c can also be written as a(b+c)=ab+ac.

3. Definition of equation

The formula of equality. Connecting two algebras with "=" means that the two algebras are equal.

4. Properties of the equation

Both sides of the equation add and subtract the same number at the same time, multiply and divide the same number (except 0), and the equation still holds. If a+b=c, adding 3 on both sides at the same time still holds, that is, a+b+3 = c+3; It is also true that both sides are multiplied by 3 at the same time, that is, 3(a+b)=3c.

5, simple equation definition

Equations with unknowns are called equations. The exponents of the unknowns of simple equations are all 1, also called linear equations. An equation must be an equation, but an equation is not necessarily an equation. For example, a+3=6 is an equation, and 3+3=6 is an equation, but it is not an equation.

The value of the unknown quantity that makes the two sides of the equation equal is called the solution of the equation, and the process of solving the equation is called solving the equation. Equations play an important role in mathematics learning and daily life.