# NCERT Solutions for Class 7 Maths Chapter 12 Exercise 12.1

NCERT Solutions for Class 7 Maths Chapter 12 Exercise 12.1 (Ex. 12.1) Algebraic Expression updated for academic session 2020-2021 free to use online or download. All the solutions and study material are available in PDF and videos format.

In class 7 math exercise 12.1 we will study about the basic terms related to algebraic expression. We will try to know about variables, constants, factors, coefficients, and other terms related to ex. 12.1 of standard 7th mathematics.## Class 7 Maths Chapter 12 Exercise 12.1 Solution

Class: 7 | Mathematics |

Chapter: 12 | Algebraic Expressions |

Exercise: 12.1 | Hindi and English Medium Solution |

### CBSE NCERT Class 7 Maths Chapter 12 Exercise 12.1 Solution in Hindi and English Medium

### Class 7 Maths Chapter 12 Exercise 12.1 Solution in Videos

#### Algebraic Expressions

A combination of constants and variables connected by some or all of the four fundamental operations +, -, x and ÷ is called an algebraic expression.

#### Constants and Variables

In Algebra, we come across two types of quantities, namely constants and variables.

##### Constant

A symbol having a fixed numerical value is called a constant.

##### Variable

A symbol which takes various numerical values is known as a variable.

Examples:

(i) The perimeter P of a square of side S is given by the formula, P = 4 x S.

Here 4 is a constant while P and S are variables.

(ii) The circumference C of a circle of radius R is given by the formula, C = 2πR

Here 2 and π are constants while C and R are variables.

##### Terms of an Algebraic Expression:

The different parts of the algebraic expression separated by the sign + or -, are called the terms of the expression.

Examples:

(i) 5 – 3x + 4 x²y is an algebraic expression consisting of three terms, namely 5, -3x and 4x²y.

(ii) 7x² -5xy + y² z – 8 is an algebraic expression consisting of four terms, namely 7x², -5xy, y² z and -8.

##### Various Types of Algebraic Expressions

(i) Monomials

(ii) Binomials

(iii) Trinomials

(iv) Quadrinomials

(v) Polynomials

##### Monomials

An algebraic expression which contains only one term, is called a monomial. Thus 5x, 2xy, -3a², b, -7, etc., are all monomials.

##### Binomials

An algebraic expression containing two terms is called a binomial. Thus, (2a + 3b), (8 – 3x), (x² – 4xy²), etc., are all binomials.

##### Trinomials

An algebraic expression containing three terms is called a trinomial. Thus (a + 2b + 5c), (x + 2y – 3z), (x³ –y³ –z³), etc., are all trinomials.

##### Quadrinomials

An algebraic expression containing four terms is called a quadrinomial. Thus (x + y + z – 5), (x³ + y³ + z³ + 3xyz), etc., are all quadrinomials.

##### Polynomials

An expression containing two or more terms is called a polynomial.

##### How are algebraic expressions used in real life?

You can liken algebra to an all-purpose tool or a magic wand that can help deal with everyday problems of life. Algebra can help you to measure your living room dimensions and determine the size of an electronic item like TV or refrigerator that’ll fit comfortably in the space.

##### Why are algebraic expressions useful?

Algebraic expressions are useful because they represent the value of an expression for all of the values a variable can take on. Similarly, when we describe an expression in words that includes a variable, we’re describing an algebraic expression, an expression with a variable.

##### Why do we use algebra?

Algebra can be used to predict sales and how much a customer will spend. Algebra is used to estimate the life time value of a customer, which calculates the percentage of annual spend. Algebra is used because x (the number of months a customer has shopped with us) can change.