8.8.B
The Standard
write a corresponding real-world problem when given a one-variable equation or inequality with variables on both sides of the equal sign using rational number coefficients and constants
Texas Essential Knowledge and Skills for Mathematics
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students invent a realistic situation that fits a given symbolic comparison. They define the variable and explain what each rate, starting amount, and comparison symbol means in the situation.
What Mastery Looks Like
- A student defines one variable clearly and connects every coefficient and constant to part of the situation. The wording matches the comparison symbol, and both expressions describe quantities measured in the same units. The context also makes sense for likely variable values.
Common Misconceptions
- Students may give the variable different meanings on the two sides or leave a term out of the story. They often swap the starting amount and rate, or reverse the inequality when using phrases like “at least” and “no more than.” Some create contexts where the variable cannot sensibly take the allowed values, such as half a person.
How to Assess It
- Exit ticket: Write a realistic problem for 18 + 1.25n ≥ 6 + 2.75n. Define n and explain what each number and the comparison symbol mean.
Lesson moves
Ways to Teach It
Give groups cards showing starting fees, per-item rates, quantities, and comparison symbols, then have them build and narrate matching situations.
Ask, “What story could 12 + 2.5x ≤ 30 + 1.5x tell, and what does x mean?”
Run a card match with equations, inequalities, and story cards, then require students to correct one near-match.
Compare two phone, taxi, or rental plans, then write a customer question that matches the resulting equation or inequality.
Keep exploring
Related Standards
- 8.8.C
model and solve one-variable equations with variables on both sides of the equal sign that represent mathematical and real-world problems using rational number ...
- 7.10.C
write a corresponding real-world problem given a one-variable, two-step equation or inequality
- 8.8.A
write one-variable equations or inequalities with variables on both sides that represent problems using rational number coefficients and constants
- 6.9.C
write corresponding real-world problems given one-variable, one-step equations or inequalities
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