# Algebraic Expressions Class 7 Notes: Chapter 12

Algebraic expressions class 7 notes i.e. for chapter 12 provided here are one of the most handy resources for the class 7 students. These chapter 12 notes can help students to not only learn the concepts from this chapter easily but can also help them to revise this chapter efficiently. The topics covered here include-

• What is an algebraic expression?
• Meaning and types of terms
• Types of expressions
• Important points
• Practice questions

## What is an Algebraic Expression?

Algebraic expression is a kind of expression which is formed by the combination of variables and constants. For example, 3x+ 2y is an algebraic expression and in this expression, “x” and “y” are variables while 3, and 2 are constants. Check out algebraic expressions to learn more details about this topic.

### Terms and its Types

In an expression, terms are separate parts which are added together. A term is generally a product of different factors. For example, in an expression, 3×2 + 2, 3×2 and 2 are different terms. In this, the term 3×2 has three factors which are 3, x, and x. It should be noted that any factor which contains variables are known as algebraic factors.

There are two main types of terms which are-

• Like terms: these are the terms which have same algebraic factors. For example, in an expression 2xy – 6xy + 4x, 2xy and -6xy are like terms.
• Unlike terms: there are the terms which different algebraic factors are known as unlike terms. In the same expression above i.e. 2xy – 6xy + 4x, 2xy and 4x are unlike terms.

### Types of Expressions

Based on the number of terms, an expression can be categorised into three main types-

• Monomials: in this type of expression, there is only one term. Example: 5×3, 2×5, etc.
• Binomial: these expressions have two unlike terms. Example: 2xy + 3, 4x2y + 3, etc.
• Trinomial: these kind of expression have three terms. Example: 2×2 + 3x + 2, 3×3 + 2x + 7, etc.

### Other Important Points

• The numerical factor in a term is called the coefficient.
• To calculate the sum or difference of two like terms, add or subtract the coefficients of the like terms. For example, 2xy + 3xy = (2+3)xy =5xy.
• When adding two algebraic equations, like terms are only added while the unlike terms are kept as it is. For example, the summation of two expression i.e. 2×2 +3x, and 5x + 4 will be 2×2 + 8x + 4.
• A value of an expression can be found if the value of the variable is given. For example, the value of the expression 3x + 2 for (x = 2) will be 8.
• The successor of any natural number “n” will be (n+1) while its predecessor will be (n-1).
• For any natural number “n”, 2n will always be an even number while (2n + 1) will always be an odd number.

### Practice Questions

1. Complete the values from this table:

1. Find the terms and factors of the following equations:
1. $a-3$
2. $1+a+a^{2}$
3. $y-y^{3}$
4. $5ab^{2}+7x^{2}y$
5. $-xy+2y^{2}-3x^{2}$
1. Classify the following into monomial, binomial, or trinomial
1. $4b-7a$
2. $b^{2}$
3. $a+b-ab$
4. $50$
5. $ab+b+a$
6. $5+10x$