# Class 7 Maths Chapter 12 Algebraic Expressions

NCERT SOLUTIONS FOR CLASS 7 MATHEMATICS
ALGEBRAIC EXPRESSIONS – Lesson 12
Summary:
*Algebraic expressions are formed from variables and constants.
*We use the operations of addition, subtraction, multiplication and division on the variables and constants to form expressions.
* A term is a product of factors. Factors containing variables are said to be algebraic factors.
* The coefficient is the numerical factor in the term.
* Any expression with one or more terms is called a polynomial.
* A one term expression is called a monomial.
* A two term expression is called a binomial.
* A three term expression is called a trinomial.
* Terms which have the same algebraic factors are like terms.
* Terms which have different algebraic factors are unlike terms.
* The sum (or difference) of two like terms is a like term with coefficient equal to the sum (or difference) of the coefficients of the two like terms.
* When we add two algebraic expressions, the like terms are added as given above: the unlike terms are left as they are.
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Exercise 12.1
1. Get the algebraic expressions in the following cases using variables, constants and arithmetic operations.
i) Subtraction of z from y.
ii) One – half of the sum of numbers x and y.
iii) The number z multiplied by itself.
iv) One – fourth of the product of numbers p and q.
v) Numbers x and y both squared and added.
vi) Number 5 added to three times the product of numbers m and n.
vii)Product of numbers y and z subtracted from 10.
viii) Sum of numbers a and b subtracted from their product.

algebraic expressions-converted