8th Grade · Expressions & Equations
Define the Variable
8.EE.C.7b
Definition
Clearly state what an unknown letter represents, including its units, before writing an equation. This is the first step in solving a word problem.
Examples
- Let x = the number of miles.
- 'Let x = the taxi' is vague; 'let x = number of miles' is clear.
Key rule
Always write 'Let x = ...' with units.
Memory hook
Say exactly what the letter stands for.