Addition and subtraction of algebraic expressions is an important concept in mathematics, which involves the basic operation and deformation of algebraic expressions. I will help you better understand the addition and subtraction of algebraic expressions through a video explanation.

First, let's look at the definition of algebra. Algebraic expressions refer to those formulas that only contain four operations of addition, subtraction, multiplication and division, without brackets and denominator. For example, 2x, 3y and 4z are all algebraic expressions.

Next, let's look at the addition and subtraction rules of algebraic expressions. Addition and subtraction of algebraic expressions are realized by merging similar terms. Specifically, if two algebraic expressions contain the same letters and the same letter index, they are called similar terms. Merging similar terms means adding their coefficients to get a new algebraic expression.

Now, we explain the addition and subtraction of algebraic expressions through a concrete example. Suppose we have two algebraic expressions A and B, which are 2x+3y and 4x+2y respectively. We need to find the sum of these two algebraic expressions.

First of all, we can see that the letters contained in these two algebraic expressions are X and Y, and their indexes are 1. Therefore, we can merge these two algebraic expressions.

Next, let's add up the coefficients first. The coefficient of 2x is 2 and the coefficient of 4x is 4, so the coefficient of merging X is 2+4=6. Similarly, the coefficient of 3y is 3 and the coefficient of 2y is 2, so the coefficient of merging y is 3+2=5.

Finally, we multiply the merged coefficients to get a new algebraic expression 6x+5y. This is the sum of the original two algebraic expressions.

From this example, we can see that the addition and subtraction of algebraic expressions is actually adding the coefficients of similar terms to get a new algebraic expression. This process can be expressed by a simple mathematical model: if two algebraic expressions are similar terms, then their sum is the sum of their coefficients multiplied by the index of the same letter.

The above are the basic concepts and operation rules of algebraic addition and subtraction. I hope you can better understand the algebraic addition and subtraction through this video. If you have any other questions or questions, please feel free to ask me.