Linear Inequalities- Do Now Activities
What Is a Do Now and Why Does It Actually Matter
A Do Now is a short activity students complete at the start of class. It takes 5-10 minutes. It reviews previous material or introduces a concept that'll come up in the lesson.
That's it. No magic. No engagement trick. Just purposeful practice that keeps skills fresh.
For linear inequalities, Do Nows serve one job: make sure students can solve and graph these before you pile on the complicated stuff later.
Why Linear Inequalities Need Dedicated Do Nows
Linear inequalities are easy to forget. Students solve them once, move on, and by the next unit they've lost the difference between "<" and "≤".
Graphing gets worse. They forget which side of the line to shade. They mix up solid and dashed boundary lines. They flip the inequality sign when they shouldn't.
Regular Do Nows catch these gaps before they become permanent habits.
Types of Do Now Activities for Linear Inequalities
Quick Solve Problems
Give students 2-3 inequality problems to solve. Vary the format:
- Solve and graph: 2x + 3 < 7
- Write the inequality from a graph
- Solve: -4x - 2 ≥ 10
Keep it tight. Three problems max. If they can't finish three problems in five minutes, you have a bigger problem than your Do Now design.
Error Analysis Tasks
Show a worked-out solution with a mistake. Students find and correct it.
This works because it forces active reading instead of passive solving. They're not just doing math—they're evaluating math.
Example: A student solved 3x - 1 > 8 and got x > 3. Is this right? Find the mistake.
Comparison Tasks
Present two graphs or two inequalities. Students identify similarities and differences.
- How is y ≤ 2x + 1 different from y < 2x + 1?
- Which inequality matches this graph? (give multiple choice)
These build conceptual understanding that solving drills alone won't.
Number Line Sorts
Give students a set of inequalities and number lines. They match each inequality to its correct number line representation.
Great for visual learners. Also reveals instantly who understands the connection between inequality notation and number lines.
Ready-to-Use Do Now Templates
Template 1: The Warm-Up Drill
Time: 5 minutes
Format: Individual, then pair-share
- Solve: 5x - 3 > 12
- Graph the solution on a number line
- Is x = 4 a solution? Show your work.
Why this works: It hits solving, graphing, and testing a solution—all core skills.
Template 2: The Graph-to-Inequality Challenge
Time: 7 minutes
Format: Partner work
Give students a graph with a boundary line and shaded region. They write the inequality that represents the graph.
Then they swap with a partner. Partner writes the inequality, then graphs it to check if it matches.
Why this works: Reversing the process builds deeper understanding. Students see both directions of the skill.
Template 3: The Mistake Hunter
Time: 5 minutes
Format: Individual
Present this work:
"Solve: -2x + 5 ≥ -3"
"-2x ≥ -8"
"x ≥ 4"
Students identify the error. The truth: there's no error in this one. Sometimes the trick is recognizing correct work.
Mix in real errors too:
"Solve: 4x + 1 < 9"
"4x < 8"
"x > 2"
Students catch the sign flip that never happened.
Systems of Linear Inequalities Do Nows
Once students master single inequalities, systems are the next battle.
The Feasible Region Task
Give students a system:
- y > x + 2
- y ≤ -x + 5
Students graph both and identify the feasible region.
Common mistake: shading the wrong side for one or both inequalities. The Do Now reveals this fast.
Point-Testing Do Now
Give students a graph with a feasible region. They test three points:
- One inside the region
- One outside the region
- One on a boundary line
They verify each point satisfies the system.
This builds intuition for what "solution to a system" actually means.
Do Now Structure That Actually Works
Don't overthink this. Use this simple framework:
- Minutes 0-1: Students get to desks, open books, see the problem. No instructions needed if the format is consistent.
- Minutes 1-5: Students work independently. You walk, observe, take notes on who struggles.
- Minutes 5-7: Quick share or turn to neighbor. Compare answers. Argue briefly if needed.
- Minute 7-8: Brief debrief. Two or three students share. You correct misconceptions on the spot.
That's it. Eight minutes maximum. Any longer and you're eating into instruction time.
How to Differentiate Do Nows
Not all students need the same level. Here's how to handle it:
| Student Level | Do Now Adjustment |
|---|---|
| Struggling | Give one problem instead of three. Use simpler numbers. Provide a number line template. |
| On-level | Standard problems. Expect complete work in five minutes. |
| Advanced | Include a system of inequalities or a word problem. Push for multiple representations. |
You don't need different Do Nows for every student. Create two versions: one scaffolded, one standard. Done.
Common Mistakes to Watch For
These show up in Do Nows constantly. Address them directly:
- Flipping the sign when multiplying/dividing by negative: This is the most common error. Every Do Now that involves negative coefficients will surface it.
- Confusing boundary line styles: ">" and "<" need dashed lines. "≥" and "≤" need solid lines. Students forget this constantly.
- Shading the wrong region: Test a point. If it works, shade that side. If it doesn't, shade the other side.
- Writing inequalities backwards: "x is greater than 3" is x > 3, not x < 3. Language matters.
Getting Started: Your First Week Plan
Day 1: Solve and graph three linear inequalities. Keep numbers simple. Establish the routine.
Day 2: Error analysis. Show a common mistake. Students find and fix it.
Day 3: Graph-to-inequality. Students write inequalities from graphs. Partner check.
Day 4: Number line matching. Physical matching activity if possible. Digital if not.
Day 5: Mixed review. Three problems, one from each previous type. Assess who has it and who doesn't.
By end of week one, you'll know exactly which students need intervention and which are ready to move on.
What to Do When Do Nows Reveal Big Gaps
If more than half your class bombs the Do Now, you have an instruction problem, not a Do Now problem.
Stop the lesson. Re-teach the concept. Don't push forward just because the schedule says so.
The Do Now told you something. Listen to it.
If it's a few students, pull them during independent practice. Give them a modified version of the Do Now with more scaffolding. Don't ignore the signal.
Digital Do Now Options
Some teachers prefer digital. Here are real options:
- Desmos: Interactive graphing. Students can check their own work instantly.
- Google Forms: Quick multiple choice or numeric entry. Auto-grades. You get data fast.
- Kahoot or Blooket: Game-format practice. Works for review, but don't use it every day—it becomes entertainment, not practice.
Digital works. Paper works. Pick what you'll actually use consistently and stick with it.
The Bottom Line
Do Nows for linear inequalities aren't revolutionary. They're not exciting. They don't need to be.
They need to be consistent, targeted, and brief.
Three problems. Five minutes. Every class. That's the whole system.
Stop overcomplicating it. Students solve, graph, and check. You observe and adjust. That's the job.