6th Grade · Expressions & Equations
Substitution
6.EE.A.4
Definition
Replacing a variable with a given value, often used to check if expressions are equivalent.
Examples
- Plug x = 4 into both 2(x+3) and 2x+6 — both equal 14.
- Substitution tests whether two expressions match.
Key rule
Use substitution to check if expressions are equivalent.
Memory hook
Plug in the same number, compare the results.