7.EE.A.2 7th Grade Expressions & Equations

Rewriting Expressions

Understand that rewriting an expression in different forms can show how the quantities in a problem are related.

How to explain it

The anchor students hold onto: Combine like terms (same variable part), distribute the factor to every term inside parentheses, and remember that a means 1a. The rewritten form has the same value — only the form changes.

Rewriting equivalent expressions supports 7.EE.B.3–4 multi-step equations and Algebra 1 simplifying. The percent-as-coefficient model (1.05a) underpins markup and growth in 7.RP.A.3.

Worked examples

Example 1 Like Terms

Rewrite: 5x + 2x.

Step 1Both terms have the same variable part: x.

Step 2Add the coefficients: 5 + 2 = 7.

Answer7x

Example 2 Distribute

Rewrite: 3(x + 4).

Step 1Multiply 3 by each term inside.

Step 23 times x is 3x; 3 times 4 is 12.

Answer3x + 12

Example 3 In Context

Rewrite: a + 0.05a.

Step 1a means 1a, so this is 1a + 0.05a.

Step 2Add the coefficients: 1 + 0.05 = 1.05.

Answer1.05a (a 5 percent increase)

Common mistakes

What students write Combines unlike terms: writes 3x + 4 as 7x.

The fix Only combine same-variable terms. 3x and 4 are unlike.

What students write Distributes to the first term only: 3(x + 4) gives 3x + 4.

The fix Multiply the factor by EVERY term: 3(x + 4) = 3x + 12.

Teacher tip

Head off the two predictable errors before they happen. First: Only combine same-variable terms. 3x and 4 are unlike. Second: Multiply the factor by EVERY term: 3(x + 4) = 3x + 12.