Understanding the Concept: Combining Like Terms in Mathematics

In the vast and intricate world of algebra, mastering the concept of combining like terms stands as a crucial foundational skill. This technique, simple in its essence, dramatically simplifies algebraic expressions and equations, making complex mathematical problem-solving more accessible. By identifying and merging terms with common variables and powers, mathematicians can condense equations to their most succinct form.

This article will provide a comprehensive understanding of what it means to combine like terms, how to do it effectively, and the importance of this process in mathematics, all illustrated with relevant examples.

What are Like Terms?

Before we dive into combining like terms, let’s start with combining like terms definition:

In mathematics, like terms, refer to algebraic expressions that share the same variable to the same power. This means that both the variable and its exponent must be identical. These shared components can be multiplied by any constant, which could be different for different terms.

Example: Consider the following terms: 5x, 3x, and 7x2.

  • The terms 5x and 3x are like terms because they share the same variable (x) raised to the same power (1, in this case).
  • However, 7x2 isn’t a like term to 5x and 3x because, though it has the same variable (x), the power (2) is different.

Process of Combining Like Terms

Combining like terms involves adding or subtracting the numerical coefficients of like terms to simplify the expression or equation. When the coefficients are added together or subtracted, the resulting term remains a ‘like term’ because it has the same variable and the same power.

Steps to Combine Like Terms

  1. Identify like terms: Look for terms with the same variables raised to the same power.
  2. Addition or subtraction: Combine the coefficients of the like terms by addition or subtraction, depending on the operation sign in front of the terms.
  3. Write the resulting term: The combined term will have the same variable and exponent.

Example of Combining Like Terms

Consider the expression: 5x + 3x – 7x2 + 9x2 – 2x + 8 – 4.

First, identify the like terms:

  • Like terms with x: 5x, 3x, and -2x
  • Like terms with x2: -7x2 and 9x2
  • Constants: 8 and -4

Next, add or subtract the coefficients of the like terms:

  • Combine coefficients of x: 5x + 3x – 2x = 6x
  • Combine coefficients of x2: -7x2 + 9x2 = 2x2
  • Combine constants: 8 – 4 = 4

The simplified form of the original expression is: 2x2 + 6x + 4.

The Importance of Combining Like Terms

Combining like terms plays a crucial role in many areas of mathematics. It is employed in solving linear and quadratic equations, simplifying polynomial expressions, and in various multiplier situations. It is a basic tactic in algebra that allows for brevity and clarity, generating mathematically crisp and less complex solutions.

Quick Tips for Combining Like Terms

  • Consider Sign Changes: Always pay attention to the operation signs before each term. The sign before a term belongs to that term. Therefore, a change in sign means a change in operation.
  • Practice Regularly: By combining like terms and other algebraic simplification techniques, proficiency comes with practice. Regularly working with various expressions will make identifying and combining like terms almost instinctive.


In essence, combining like terms is an indispensable tool in the world of algebra. It condenses our expressions and equations into their simplest forms, allowing for enhanced understanding and easier problem-solving. By practicing the identification and merging of like terms, one can significantly improve their mathematical dexterity, thus paving the way for more complex and fascinating algebraic explorations.