Practice Set · Part 1
Write and Represent Inequalities
Pick up where we left off
Where we left off
Our goal: I can write inequalities to represent real-world situations, explain what each part stands for, and build one for a situation I have not seen before.
The big idea: Decide if the boundary number is allowed and which way the values go, then choose the symbol that matches both.
Model to copy — Example · "No less than"
- To win a prize, a player must score no less than 25 points. Write an inequality for the score s.
- Read the whole phrase: no less than 25
- Decide if 25 is included: 25 ✓
- Pick the symbol: ≥
- Write the inequality: s ≥ 25
- s ≥ 25. A score of 25 or more wins a prize.
Start here
You did these with your group. Now do them on your own — the model above is yours to copy.
- 1
Same stepsFinish what the group started. Use the model above, step for step.
Try it together — then prove it: Clue: "A bag holds fewer than 10 items." Write an inequality for the number of items n. What does "fewer than" mean? Is 10 included? (It means less than. 10 is not included.) Write the inequality. (n < 10) Why is n ≤ 10 wrong for this clue? (n ≤ 10 includes 10. But a bag with 10 items does not hold fewer than 10.)Show your work - 2
Warm restartSolve: 6x = 42
- Ax = 7
- Bx = 36
- Cx = 48
- Dx = 252
How do you know?
- 3
Warm restartSolve: n / 3 = 8
- An = 3
- Bn = 5
- Cn = 11
- Dn = 24
How do you know?
- 4
Warm restartSolve: 9m = 63
- Am = 7
- Bm = 54
- Cm = 72
- Dm = 567
How do you know?
Practice Set · Part 2
Write and Represent Inequalities
Keep going
You answered these out loud. Now write them.
Answer, then say how you know — the reason is the part that counts.
- 5
Think it throughWhich speed is NOT possible for the getaway car?
- A45 mph
- B60 mph
- C65 mph
- D70 mph
Why is that the answer?
- 6
Think it throughDoes s ≤ 65 include 65 itself?
- ANo — it must be strictly less
- BYes — the 'or equal to' part includes 65
- COnly if the car stops
- DOnly on a highway
How do you know? Give a second reason as well.
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Think it throughWhich inequality means 'at most 65'?
- As ≤ 65
- Bs < 65
- Cs ≥ 65
- Ds > 65
Explain your thinking. What would have to change for a different choice to be right?
- 8
Back to the modelHow do the words 'at least' and 'at most' change the inequality symbol compared to 'more than' and 'fewer than'?
Practice Set · Part 3
Write and Represent Inequalities
Words and reasoning
Word bank · Banco de palabras
Use the words
Fill each blank with a word from the bank.
- A math sentence comparing values with <, >, ≤, or ≥ is an ___.
- The symbol > that means one value is larger than another means ___.
- The symbol < that means one value is smaller than another means ___.
- 'At least' means greater than or equal to, and 'at most' means ___ than or equal to.
Explain the thinking
- 9
Find the mistakeAnother student made this exact mistake in this lesson. Explain why it is wrong, then write what they should have done.
The mistake: A common mistake in Write Inequalities is using a strict symbol (> or <) for a phrase that actually includes the boundary value. - 10
Say moreHow do the phrases 'at least' and 'at most' change which inequality symbol you choose compared to 'more than' and 'fewer than'?
- 11
Write your ownWrite your own problem about this situation, then solve it and show the answer. The situation: Three balance scales are shown. On two of them the pans hang at different heights, so one side is heavier. On the third the pans are level.
Show your work
Practice Set · Part 4
Write and Represent Inequalities
Show what you know
Last check
These two come from Lesson 8.3. If they are shaky, that is the lesson to revisit — not this one.
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Show what you knowExplain your thinking — Which inequality represents: 'A number n is at least 14'?
- An ≥ 14
- Bn > 14
- Cn ≤ 14
- Dn < 14
Explain your choice.
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From Lesson 8.3Explain your thinking — Solve: w / 8 = 6
- Aw = 0.75
- Bw = 2
- Cw = 14
- Dw = 48
How do you know?
- 14
From Lesson 8.3Check: does 9 work?
- AYes — 7 × 9 = 63
- BNo — 7 × 9 = 56
- CNo — 7 + 9 = 16
- DOnly if kits cost $9
How do you know?
Be honest — this tells your teacher what to do next
| I can… | Not yet | Getting there | Got it |
|---|---|---|---|
| I can write inequalities to represent real-world situations, explain what each part stands for, and build one for a situation I have not seen before. | |||
| I can explain why it works: Decide if the boundary number is allowed and which way the values go… | |||
| I can justify my answer to a skeptic and connect it to a second strategy or representation. |
One question I want to ask my group next time