Lesson 9.49.4 Small Group · Group 1
Start hereWords, worked example, and sentence starters
Learning target With my small group, I can write an equation to represent the relationship between two variable quantities and use it to solve a real problem — one step at a time, with support.
Start hereWords for this lesson
Read each word before you begin. Say it out loud.
| Word | What it means | Example |
|---|---|---|
| solutionSpanish: solución | A value of the variable that makes an equation true. | the number you solve for |
| substituteSpanish: sustituir | To replace a variable with a number so you can compute. | put 8 in for x |
| at leastSpanish: al menos | That amount or more — the smallest amount that still works. | “At least $500” means $500 counts, and so does anything more. |
| predictSpanish: predecir | To make a reasonable guess about a future amount using information you already have. | We measured up to 5 minutes → 6,000 feet. Reach PAST what was measured: 6 minutes should be about 7,200. |
| justifySpanish: justificar | To explain WHY an answer or recommendation makes sense, using the mathematics. | “35 cars at $14.30 raises $500.50, which clears the $500 goal.” |
| EquationSpanish: Ecuación | A math sentence with an equals sign showing two amounts are the same. | c = 4n |
How it worksWorked examplesubstituting to find the output
These numbers are not on your problems. The steps are. Follow them with your own numbers.
A press makes 22 posters each hour. Write an equation, then find the posters made in 15 hours.
- Define: h = hours running, p = posters made. Posters depend on hours.
- The rate is 22 posters for each hour, so the rule is p = 22h.
- Substitute 15 for h: 22 × 15 → 330 posters.
- Check the context: many more hours gave a much larger count, so this fits.
Answer: p = 22h, so a 15-hour run makes 330 posters.
Now you trySame steps, your turn
The steps are the same as the worked example. The numbers are yours. Do the work.
A juicer fills 13 bottles each minute. Write an equation, then find the bottles filled in 40 minutes.
- Define: m = , b = .
- The rate is bottles for each minute, so the rule is b = m.
- Substitute 40 for m: × 40 → bottles.
- Check the context: does your answer fit that many minutes?
Say it and write itSentence starters
Finish each sentence out loud with a partner. Then use them in your writing.
- I let stand for and stand for .
- My equation is , so I substitute for .
- The solution is , which means in this situation.
- This answer is reasonable because .
Word bank equationsubstitutesolutionratevariablemultiplypertotalreasonablecheckinputoutput
Watch outA common mistake
Adding the rate instead of multiplying — writing 2.5 + 8 = 10.5 cars for an 8-hour shift instead of 2.5 × 8 = 20. The rate applies to EVERY hour, so the total is always rate × amount.
Lesson 9.49.4 Small Group · Group 1
Group 1Supported practice
Learning target With my small group, I can write an equation to represent the relationship between two variable quantities and use it to solve a real problem — one step at a time, with support.
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1Complete each step, then write the final answer.
The bakery makes 1.5 cakes each hour. A bakery makes 1.5 cakes every hour. It gets an order for 60 cakes. Let h = hours and c = cakes. How many hours does the bakery need? It works 8 hours a day. How many days is that?
- 1Write an equation for the cakes made in h hours.
- 2Substitute 60 for c. What equation do you get?
- 3Divide both sides by 1.5. How many hours?
- 4The bakery works 8 hours a day. How many days is that?
Final answer: -
2Complete each step, then write the final answer.
Each bracelet raises $3. A club sells bracelets for $3 each. Their goal is $100. Let b = bracelets sold and t = total raised. How many bracelets must they sell?
- 1Write 1 bracelet → $3. What scale factor takes $3 to $100?
- 2How much money do 33 bracelets raise?
- 3What is the least number of bracelets that reaches $100?
Final answer: -
3Complete each step, then write the final answer.
The machine fills 5 boxes each minute. A machine fills 5 boxes every minute. Let m = minutes and b = boxes. How many minutes does it take to fill 45 boxes?
Show your workHint The equation is b = 5m. Put in 45 for b. Then divide both sides by 5.
Final answer: -
4Complete each step, then write the final answer.
The factory makes 3.5 bikes each hour. A factory makes 3.5 bikes every hour. Let h = hours and b = bikes. How many hours does the factory need to make 280 bikes?
Show your workHint Write b = 3.5h. Put in 280 for b. Which operation undoes multiplying by 3.5?
Final answer: -
5Complete each step, then write the final answer.
Each plant earns $8. A school earns $8 for each plant it sells. The goal is $150. Let p = plants sold. What is the least number of plants they must sell to reach the goal?
Show your workHint Solve 8p = 150. The answer is not whole. Check the whole numbers on each side of it.
Final answer: -
6Circle the letter of the best answer. Show how you know.
Each notebook costs $3. Kim has $20. Kim has $20. Notebooks cost $3 each. She solves 3n = 20 and gets n ≈ 6.7. She says she can buy 7 notebooks. Is she right?
- ANo. 7 notebooks cost $21, so she can buy 6.
- BYes. 6.7 rounds up to 7.
- CNo. She can buy 6.7 notebooks.
Hint Find the cost of 7 notebooks. Can Kim pay for them with $20?
Show your work
Explain your thinkingThe bracelets needed 34, not 33.3. Kim could buy 6, not 6.7. When do you round up, and when do you round down?
Sentence starter I round up when ___. · I round down when ___.