Addition and subtraction of algebraic expressions

Addition and Subtraction of Algebraic Expressions

We learn how to add or subtract numbers like 12 and 17. We even know how to add positive numbers with negative ones. For example, adding (-22) and (+103). But, class 8 mathematics solutions are not all about numbers.

We have read about the use of letters or we can say variables in mathematics. Such expressions are called algebraic expressions.

Addition and subtraction of algebraic expressions

In order to learn the ways of addition and subtraction of algebraic expressions, the rules of general addition and subtraction of numbers are required. There are terms that have the same power and variable.

Then, there are unlike terms that can be different in terms of variables or power. We have to understand the difference between these terms.Let us see how to add algebraic expressions.

How to add algebraic expressions?

Before we start understanding how to add algebraic expressions, we should know that the addition of algebraic expressions takes place between like terms only. Look at the example below.

So, we can see the addition of algebraic expressions is applicable for like terms like (-4x and 9x) or (5 and -10). Here, (7x2) was a completely different term.

So, the first thing we need to understand about how to add algebraic expressions is to look for the like terms. Group these terms and add them. We have learned how to add algebraic expressions, let us learn how to subtract algebraic expressions.

Also read: NCERT Solutions for Class 8 Maths

Subtraction of algebraic expressions

The rules for the subtraction of algebraic expressions are similar to those for the addition of algebraic expressions. The first thing we do is to look for like terms. Look at the example shown below.

Here, we can see that (5a2 and -2a2) are like terms. In a similar way, the two terms (-7ab and 3ab) are considered as like terms. Subtraction of algebraic expressions is also possible between the like terms. After looking at the examples shown above, we know how to subtract algebraic expressions.

We have also observed that the rules for addition and subtraction of algebraic expressions are similar.

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NCERT Solutions for Class 8 Maths
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