Lesson 8.38.3 Small Group · Group 2
Start hereWords, worked example, and sentence starters
Learning target I can solve one-step multiplication and division equations using inverse operations, explain why the method works, and use it on a problem I have not seen before.
Why This Matters This is your challenge small group for Lesson 8.3. You can already get the answer — so in here the answer is the starting point. We ask when the method holds, when it breaks, and how you would convince someone who disagrees.
Start hereWords for this lesson
Read each word before you begin. Say it out loud.
| Word | What it means | Example |
|---|---|---|
| Inverse operationSpanish: Operación inversa | Two math actions that undo each other, like × and ÷. | × and ÷ |
| MultiplySpanish: Multiplicar | To add equal groups again and again. | 3 × 7 = 21 means 3 groups of 7 equals 21 |
| DivideSpanish: Dividir | To split into equal groups. | 20 ÷ 4 = 5 |
| IsolateSpanish: Despejar | To get the letter by itself on one side. | get p by itself |
| CoefficientSpanish: Coeficiente | The number in front of a letter, like the 3 in 3x. | the 3 in 3x |
| SolutionSpanish: Solución | A number that makes the equation or inequality true. | x = 3 is the solution of 6x = 18 because 6 × 3 = 18. |
How it worksWorked example
These numbers are not on your problems. The steps are. Follow them with your own numbers.
5 boxes each hold the same number of pencils, 45 in all. Solve 5b = 45.
- Divide both sides by 5: 5b ÷ 5 = 45 ÷ 5.
- Simplify: b = 9.
- Check: 5 × 9 = 45.
Answer: Each box holds 9 pencils.
Now you trySame steps, your turn
The steps are the same as the worked example. The numbers are yours. Do the work.
Solve x ÷ 4 = 9. Then explain the step you used.
Say it and write itSentence starters
Finish each sentence out loud with a partner. Then use them in your writing.
- The variable is multiplied by , so I both sides by it.
- My equation is because each group holds .
- The solution means in this problem.
- I checked my answer by multiplying and .
Word bank equationcoefficientmultiplydivideinverse operationisolateboth sidesequal groupssolutioncheckundobalance
Watch out!A common mistake
A common mistake in Solve Multiplication and Division Equations is applying the SAME operation again instead of the inverse
Lesson 8.38.3 Small Group · Group 2
Group 2Challenge practice
Learning target I can solve one-step multiplication and division equations using inverse operations, explain why the method works, and use it on a problem I have not seen before.
Why This Matters This is your challenge small group for Lesson 8.3. You can already get the answer — so in here the answer is the starting point. We ask when the method holds, when it breaks, and how you would convince someone who disagrees.
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1Complete each step, then write the final answer.
8 pencils at p dollars each cost $3.20. A pack of 8 pencils costs $3.20. Each pencil costs the same. Write and solve an equation for the cost p of one pencil.
- 1Write the equation from the story.
- 2Divide both sides by 8. What is p?
- 3Check: what is 8 × 0.40?
Final answer: -
2Complete each step, then write the final answer.
Half of x is 9. Solve 0.5x = 9. Then explain the size of the answer.
- 1What is done to x? What undoes it?
- 2Divide both sides by 0.5. What is x?
- 3Check: what is 0.5 × 18?
- 4Why is x greater than 9, even though we divided?
Final answer: -
3Complete each step, then write the final answer.
Solve 12x = 3.
Show your workFinal answer: -
4Complete each step, then write the final answer.
Solve y ÷ 0.4 = 15.
Show your workFinal answer: -
5Complete each step, then write the final answer.
A car goes 210 miles on 7 gallons of gas. It goes the same distance on each gallon. Write and solve an equation for the miles m per gallon.
Show your workFinal answer: -
6Complete each step, then write the final answer.
A ribbon is cut into 6 equal pieces. Each piece is 2.5 feet long. Dev writes 6r = 2.5 for the ribbon's length r. Write the right equation. How long is the ribbon?
Show your workFinal answer: