- Books Name
- CBSE Class 7 Mathematics Book

- Publication
- Param Publication

- Course
- CBSE Class 7

- Subject
- Mathmatics

**Various definitions and concepts**

** Literals : **The letters which are used to represent numbers are called literal numbers or literals. In 2xy, x & y are the literals.

Literal numbers obey all the rules (and signs) of addition, subtraction, multiplication and division of numbers along with the properties of these operations. a × b = ab, 2 × a = 2a, 1 × a = a, x × 3 = 3x and a × a × a × ......× 15 times = a^{15}.

In a^{5}, 5 is called the index or exponent and a is called the base.

**Constant : ** A term of the expression having no literal factor is called a constant term.

(i) In the binomial expression 5x + 7, the constant term is 7. In short, a symbol having a fixed numerical value is called a constant.

**Variable :** A symbol which takes various numerical values is called a variable.

**Algebraic expression : **A combination of constants and variables connected by the signs of fundamental operations of addition, subtraction, multiplication and division is called an algebraic expression.