Free Interactive Pre-Algebra Tool

Combining Like Terms

Identify terms that belong together, combine their coefficients, simplify constants, and build the final expression one step at a time.

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Need Help With Like Terms?

Learn Why Only Like Terms Can Be Combined

Review coefficients, variables, constants, signs, and the rules for simplifying algebraic expressions.

Read the Combining Like Terms Guide

How It Works

Match the Variable Parts, Then Combine the Numbers

Like terms have the same variable part. Their coefficients can be added or subtracted, while constants combine only with other constants.

1

Identify Like Terms

Find terms with exactly the same variable part.

2

Combine Variable Terms

Add or subtract the coefficients while keeping the variable part unchanged.

3

Combine Constants

Add or subtract the number-only terms.

4

Verify the Expression

Evaluate the original and simplified expressions at the same value to confirm they match.

Interactive Practice

Simplify Each Expression

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Combine Like Terms

Medium

Find the terms that belong together, then simplify the expression.

3x + 7 + 5x − 2
Terms can be combined only when their variable parts match.
  1. 1 Identify
  2. 2 Variables
  3. 3 Simplify
1

Find the Matching Terms

Which Terms Are Like Terms?

Current Step

Current Expression

Medium

Look for terms with the same variable part.

3x + 7 + 5x − 2
The coefficients may differ, but the variable parts must match.

Choose all pairs of like terms.

2

Combine the Coefficients

Simplify the Variable Terms

Locked

Current Expression

Medium

Combine only the coefficients of matching variable terms.

3x + 7 + 5x − 2
Keep the variable part unchanged.

Enter the combined coefficient for each variable group.

3x + 5x = x
3

Finish Simplifying

Combine the Constant Terms

Locked

Current Expression

Medium

Now combine the remaining number-only terms.

3x + 7 + 5x − 2
Constants combine with constants.

Enter the value of the combined constants.

7 − 2 =

Keep This Nearby

Combining Like Terms Reference

Same variable part = like terms.

Like Terms The variable parts must match exactly. 3x and 7x are like terms
Unlike Terms Different variables cannot be combined. 3x and 3y are not like terms
Coefficients Combine the numbers in front of matching variables. 3x + 5x = 8x
Constants Number-only terms combine with each other. 7 − 2 = 5
Keep the Variable Combining coefficients does not change the variable. 4a − a = 3a
Watch the Signs A minus sign belongs to the term after it. 6x − 9x = −3x

Key Reminders

Avoid the Most Common Like-Term Mistakes

Check the variable part and the sign of every term before combining anything.

Match Variable Parts

Terms must have the same variable and exponent to combine.

2x + 6x = 8x

Do Not Combine Unlike Terms

An x-term cannot be combined with a y-term or a constant.

3x + 4y stays 3x + 4y

Carry the Sign

Treat the sign immediately before a term as part of that term.

5x − 8x = −3x

Constants Stay Separate

Combine number-only terms only with other number-only terms.

4x + 7 + 2x − 3 = 6x + 4

Keep Learning

Learn Why Like Terms Can Be Combined

Review coefficients, variables, constants, signs, and complete worked examples in the companion guide.

Read the Combining Like Terms Guide