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Last updated on September 13, 2025

Addition of Algebraic Expressions

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Adding algebraic expressions is like combining like terms. To add them, we should first identify the terms that have the same variable(s) and exponent(s); these are called like terms. We should then add only their coefficients and keep the variable part the same. In this lesson, we’ll learn how to identify like terms and add algebraic expressions step by step.

Addition of Algebraic Expressions for US Students
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What are Algebraic Expressions?

An algebraic expression is a combination of constants and variables joined by mathematical operations such as addition, subtraction, multiplication, or division. Algebraic expressions consist of variables (unknown quantities) and constants (known values)combined using mathematical operations. For example, 2x + 5y is an algebraic expression, where x and y are variables, and 2 and 5 are constants.
 

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What is the Addition of Algebraic Expressions?

To add algebraic expressions, group the like terms and add their coefficients. For example, you cannot add 2 pens and 2 pencils because they are different items, just like unlike terms in algebra. There are two simple ways to add algebraic expressions:

  • Horizontal Method 
  • Column Method 

 

 

Horizontal Method of Addition of Algebraic Expressions

 

For the addition of algebraic expressions by the horizontal method, follow the steps given below:
Step 1: Write all expressions in one line, separated by plus signs, and use brackets if needed. 
Step 2: Arrange and group the like terms. 
Step 3: Add the coefficients of the like terms while keeping the variables unchanged. 
Step 4: Write the simplified expression so that no two terms are alike.

Example:
Add: (3x + 2y) + (5x - y + 4)
Step 1: Combine in one line:
(3x + 2y) + (5x - y + 4)
Step 2: Group like terms:
(3x + 5x) + (2y - y) + 4
Step 3: Add coefficients:
8x + y + 4
Step 4: Simplified expression:
8x + y + 4

 

 

Column Method for Addition of Algebraic Expressions

 

The following steps are used for adding algebraic expressions using the column method.
Step 1: Write the expressions one below the other, aligning like terms in the same column. 
Step 2: Add the coefficients of like terms in each column.
Step 3: Combine the results from all columns to get the final expression. 

Example:
Add: 
2x2 + 3x - 4y + 7
5x + 4y -3
Step 1: Arrange the terms in a column:

Step 2: Add like terms:
2x2 - no like terms.
3x + 5x = 8x
-4y + 4y = 0
7 - 3 = 4
Step 3: Final answer:
2x2 + 8x + 4
 

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Tips and Tricks for Addition of Algebraic Expressions

When adding algebraic expressions, a few simple rules make the process easier. We only add like terms and keep the variables as they are. Using some tips, we can make the calculations faster.

  • The order of the variables in the like terms does not matter. For example, 3a + 5b and 7b + 4a still have like terms like a and b, even if the order is different.
  • We do not write 1 as a coefficient. For example, instead of writing 1xy, we write it as xy. 
  • Always combine only like terms. In 2x + 3y + 5x, we add 2x + 5x to get 7x + 3y.
  • Arrange the terms in proper order before adding. This helps to see the like terms more easily.
     
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Real Life Applications of Addition of Algebraic Expressions

The addition of algebraic expressions is used in everyday situations where we deal with quantities that have both numbers and variables. Just like we add numbers, we can add algebraic terms to find the total of similar quantities. Here are some of the real-life applications of the addition of algebraic expressions.

  • Construction and Engineering: Engineers use algebra to work with things like length, width, and height when building bridges or houses. Adding algebraic expressions helps them find the total amount or size of the material needed. 
  • Finance and economics: When planning budgets or checking profits, we use algebra to show income and expenses. Adding these expressions helps find the total money earned or spent over time. 
  • Physics: In physics, things like speed, distance, and force are often written as algebraic expressions. Adding expressions representing speed or force helps determine the net or total value in physics calculations. 
  • Shopping: When we buy different items like pencils and notebooks, their prices can be written as algebraic expressions. Adding them gives the total cost.
  • Sports: In games, scores from different rounds can be shown as algebraic expressions. Adding them gives the total score of a player or team.  
     
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Common Mistakes and How to Avoid Them in Addition of Algebraic Expressions

Mistakes are common when working with the addition of algebraic expressions. Given below are some of the common mistakes and the ways to avoid them.

Mistake 1

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Adding unlike terms
 

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 Students try to add terms with different variables or powers, like adding 3x and 5y and writing it as 8xy. Unlike terms cannot be combined because they represent different quantities. Add only the coefficients of like terms. For example, 3x + 5y are unlike terms and cannot be simplified.
 

Mistake 2

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 Ignoring the signs
 

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Students often forget to check the positive and negative signs of terms. Always pay attention to the signs when adding or subtracting. Combine the coefficients correctly. Example: Adding 4x and -3x as 7x is wrong; the correct result is 1x or x.
 

Mistake 3

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 Incorrectly arranging terms
 

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 Students sometimes do not group the like terms properly, which leads to wrong simplifications. Rearrange and group the like terms before adding. For example, 2a + 3b + 4a = (2a + 4a) + 3b = 6a + 3b
 

Mistake 4

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Confusion in exponents
 

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The common error is to add powers while adding terms, like thinking x2 + x3 = x5. This happens due to some multiplication rules. In addition, the powers must be the same for terms to be combined. If the powers are different, they remain separate.
 

Mistake 5

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Forgetting the hidden coefficient
 

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 Terms like x and y have a coefficient of 1, which students often overlook, leading to errors like x + 2x = 2x. Always remember that variables like x have a hidden coefficient of 1, so x + 2x = 3x.
 

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Solved Examples of Addition of Algebraic Expressions

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Problem 1

Add (3x + 4y) and (5x - 2y + 7)

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8x + 2y + 7
 

Explanation

Step 1: Write the expressions in one line.
(3x + 4y) + (5x - 2y + 7)
Step 2: Group like terms.
(3x + 5x) + (4y - 2y) + 7
Step 3: Add the like terms.
8x + 2y + 7
 

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Problem 2

Add (2a + 3b - c) and (4b + 5c + 6a)

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8a + 7b + 4c
 

Explanation

Step 1: Write both expressions in a line.
(2a + 3b - c) + (4b + 5c + 6a)
Step 2: Grouping like terms:
(2a + 6a) + (3b + 4b) + (-c + 5c)
Step 3: Add the coefficients
8a + 7b + 4c

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Problem 3

Add (x2 + 3x + 5) and (4x2 - x - 2)

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5x2 + 2x + 3

Explanation

Step 1: Write both the expressions together:
(x2 + 3x + 5) + (4x2 - x - 2)
Step 2: Group the like terms
(x2 + 4x2) + (3x - x) + (5 - 2)
Step 3: Add the coefficients.
5x2 + 2x + 3
 

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Problem 4

Add (p + 2q + 3r) and (4p - q + 5r)

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5p + q + 8r
 

Explanation

Step 1: Write the given expression in a single line
(p + 2q + 3r) + (4p - q + 5r)
Step 2: Grouping the like terms.
(p + 4p) + (2q - q) + (3r + 5r)
Step 3: Adding the coefficients.
5p + q + 8r

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Problem 5

Add (7m - 4n + 3) and (5n + 2m - 6)

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 9m + n - 3
 

Explanation

Step 1: Write the expressions in a line to make the simplification easier.
(7m - 4n + 3) + (5n + 2m - 6)
Step 2: Group like terms.
(7m + 2m) + (-4n + 5n) + (3 - 6)
Step 3: Add the coefficients
9m + n - 3
 

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FAQs on Addition of Algebraic Expressions

1. What is meant by adding algebraic expressions?

Combining two or more expressions by adding their like terms is known as adding algebraic expressions.
 

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2.What are like terms?

Like terms are terms that have the same variables raised to the same powers, though their coefficients can be different. 

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3.What is the difference between the horizontal and column method?

In the horizontal method, we write all expressions in one line and then group the like terms. In the column method, we arrange the expressions one below the other, aligning the like terms in the same columns, similar to how we add numbers. 

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4.Can constants be added to variables?

No, constants and variables cannot be added because they are not like terms.
 

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5.How do we check if the answer is correct or not?

To check whether the answer is correct, make sure that all like terms are combined and the final expression contains only unlike terms.

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Jaskaran Singh Saluja

About the Author

Jaskaran Singh Saluja is a math wizard with nearly three years of experience as a math teacher. His expertise is in algebra, so he can make algebra classes interesting by turning tricky equations into simple puzzles.

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Fun Fact

: He loves to play the quiz with kids through algebra to make kids love it.

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