Grade 6 · lesson 4 of 4

Combine Like Terms and Recognize Their Units

Group only terms with identical variable parts.

About 25 minutes, plus any extended practice

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Supplied materials

  • Paper and a pencil; drawing and spoken explanations are welcome. An adult may read directions and options aloud.
  • Supplied worked-case record: Rewrite 3x+5+4x as 7x+5 because three copies of x and four copies total seven.
  • All quantities and shape descriptions are supplied in the worked example and questions; no purchase or personal information is needed.

Learn the idea

Like terms contain the same variable part. Their coefficients can be combined just as equal units can be counted together. Constants are different from variable terms and must remain separate. Terms with different exponents are also not like terms. This preserves the expression’s meaning for every variable value.

Group only terms with identical variable parts. Add their coefficients and keep constants separate. Explain the grouping as counts of one common variable-sized quantity and check the rewritten expression with a supplied input.

Match the entire variable part before combining terms. Constants and variable terms are not like units. Underline like variable terms with one style and box constants separately.

  1. Underline like variable terms with one style and box constants separately.
  2. Work through the supplied example and label what each number or attribute represents.
  3. Group only terms with identical variable parts.
  4. Answer the check, then try the three changed-input practice questions and explain one correction.
Worked example

See the method in action

Rewrite 3x+5+4x as 7x+5 because three copies of x and four copies total seven. The five is a fixed amount, not five copies of x. Also, x²+x cannot become 2x² because their variable parts are different. Match the entire variable part before combining terms. Constants and variable terms are not like units. Underline like variable terms with one style and box constants separately.

Your turn

Check your reasoning

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Helpful tips
  • Match the entire variable part before combining terms.
  • Constants and variable terms are not like units.
Simplify 2x+5+3x.

Feedback appears here after you check. This is practice, not a graded school assessment.

See the answer and explanation

5x+5

Combine coefficients of x and leave the constant five unchanged.

Take it further

Simplify 6a+2+4a+7. Expected: 10a+9.

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More practice: try new cases

Choose an answer for each problem. Explain your method on paper, then use the feedback to decide what to revisit.

More practice: try new cases
1. Simplify 3x+5+3x.
Need a hint?
  • Match the entire variable part before combining terms.
  • Constants and variable terms are not like units.
2. Simplify 4x+5+3x.
Need a hint?
  • Match the entire variable part before combining terms.
  • Constants and variable terms are not like units.
3. Simplify 5x+5+3x.
Need a hint?
  • Match the entire variable part before combining terms.
  • Constants and variable terms are not like units.

Your choices are temporary. Feedback appears after you check all the answers.

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Check the subject sources

These LifeStarter passages, scenarios and exercises are authored for this Academy with AI assistance and review. External resources keep their publishers’ terms. A grade label suggests a starting level; it does not establish alignment with your school’s complete requirements.