Writing Inequalities and Constraints from Context, Algebra 1 lesson packet and Teacher Deck (HSA.CED.A.1 · HSA.CED.A.3)
HSA.CED.A.1 HSA.CED.A.3 Algebra 1 Unit 3: Linear Inequalities

Writing Inequalities and Constraints from Context

I can turn a situation into an inequality and say which answers it actually allows.

What students learn

Students learn to name a variable with its units, let each phrase choose the symbol, solve, and keep only the answers the situation allows, checking a whole number in the story.

See inside

The key rule

Name the variable and its units. Let each phrase set the symbol, solve, then keep only the values the situation allows.

at most $20 → ≤ 20

When the story counts things, test whole numbers in it: under a cap, keep the greatest that fits; to reach a minimum, the least that does.

Watch out

A lift carries at most 8 people. Write an inequality for the number of people, p.

The mistake: p < 8< leaves 8 out, but 8 people may ride.

The fix: p ≤ 8At most 8 means 8 or fewer: 8 itself counts.

The mistakes it targets

  • Uses < for at most instead of ≤
  • Uses ≥ for more than instead of >
  • Leaves out a one-time fee
  • Rounds the wrong way or keeps part of an object a story counts whole

The interactive Teacher Deck (33 slides, PowerPoint)

  • The Learn page taught on screen: 8 fill-in blanks, each filled on its own click as students write it
  • The worked example one slide per step (five steps), each with the reason for the step
  • Six practice and three apply problems: a your-turn slide with a think-time bar, then the solution one line per click
  • Jump buttons on every slide: go straight to any problem, the answer bank or the exit ticket
  • Speaker notes on each problem: the question to ask, the worked answer and the common error to listen for
  • A completed deck PDF (19 pages) with every slide fully built, to print or post

The student packet (9 pages)

  • Learn: guided notes with four definitions, the key rule, a worked example and a Watch Out error pair
  • Practice: two warm-up, two standard and two stretch problems, with an answer bank for self-checking that hides three common-mistake decoys
  • Apply: one word problem, a reasoning prompt and one error analysis
  • Assess: an exit ticket of four items, two per page, with an I-can self-rating
  • Homework (page 5): eight new problems, two warm-up, four standard and two stretch
  • Answer key (pages 6–7): every problem worked step by step, four common mistakes with what to do about each, and a grading guide, plus the homework key (page 8)
  • Color and ink-saver editions of the whole packet

Standard codes refer to the Common Core State Standards for Mathematics. Math Class 678 is an independent publisher, not affiliated with, sponsored by, or endorsed by NGA Center or CCSSO. Every product is sold on Teachers Pay Teachers.