Practice Set · Part 1
The Distributive Property
Pick up where we left off
Where we left off
Our goal: I can use the distributive property to expand and factor expressions, explain why the method works, and use it on a problem I have not seen before.
The big idea: Expanding multiplies the outside factor by every term, and factoring pulls the GCF out, so each one undoes the other.
Model to copy — Example 1 · Expand with a variable
- Expand 4(x + 3).
- Multiply 4 by the first term: 4 × x = 4x
- Multiply 4 by the second term: 4 × 3 = 12
- Add the two products: 4(x + 3) = 4x + 12
- 4(x + 3) is equivalent to 4x + 12.
- Factor 6x + 15 using the greatest common factor (GCF).
- Find the GCF of 6 and 15: 6 = 3 × 2 → 15 = 3 × 5 → GCF: 3
- Divide each term by 3: 6x ÷ 3 = 2x; 15 ÷ 3 = 5
- Write the GCF outside the parentheses: 3(2x + 5)
- Check by expanding: 3(2x + 5) = 6x + 15
- 6x + 15 is equivalent to 3(2x + 5).
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: Use the distributive property to find 2(8 + 3). Then explain a common mistake. Distribute the 2 to each term. (2 × 8 + 2 × 3) Find the value. (16 + 6 = 22) Why is 2(8 + 3) not equal to 2 × 8 + 3? (The 2 must multiply both terms. 2 × 8 + 3 = 19, and that skips 2 × 3.)Show your work - 2
Warm restartWhat is the prime factorization of 24?
- A2 × 2 × 2 × 3
- B2 × 12
- C3 × 8
- D4 × 6
How do you know?
- 3
Warm restartWhich number is prime?
- A19
- B21
- C27
- D33
How do you know?
- 4
Warm restartA factor tree for 36 ends with which prime factors?
- A2 × 2 × 3 × 3
- B2 × 18
- C3 × 12
- D6 × 6
How do you know?
Practice Set · Part 2
The Distributive Property
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 throughDistribute: 8(12 + 9) = ?
- A8 × 12 + 8 × 9
- B8 × 12 + 9
- C8 + 12 × 9
- D8 × 21 × 8
Why is that the answer?
- 6
Think it throughWhat is the total cost for 8 practice rooms?
- A$21
- B$96
- C$105
- D$168
How do you know? Give a second reason as well.
- 7
Think it throughA student wrote 8(12 + 9) = 8 × 12 + 9 = 105. What went wrong?
- AThey added instead of multiplying
- BThey used the wrong prices
- CThey forgot to multiply the 9 by 8 as well
- DThey distributed too many times
Explain your thinking. What would have to change for a different choice to be right?
- 8
Back to the modelWhat pattern do you see when you expand an expression using the distributive property?
Practice Set · Part 3
The Distributive Property
Words and reasoning
Word bank · Banco de palabras
Use the words
Fill each blank with a word from the bank.
- a(b + c) = ab + ___ — the factor reaches ___ term.
- The rule that a(b + c) = ab + ac is the ___.
- To rewrite a sum as a product, like 3x + 12 = 3(x + 4), is to ___.
- To multiply out a product over a sum, like 3(x + 4) = 3x + 12, is 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: The most common mistake in The Distributive Property is multiplying the outside factor by only the FIRST term inside the parentheses and forgetting the second — for example, writing 3(x + 4) = 3x + 4 instead of 3x + 12. - 10
Say moreWhen you expand 5(2x + 4), why must the 5 multiply BOTH terms inside the parentheses?
- 11
Write your ownWrite your own problem about this situation, then solve it and show the answer. The situation: The studio manager is ordering merch bundles for 9 band members going on tour. Each bundle includes a t-shirt ($18) and a strap ($7). The order form writes the cost two ways: 9(18 + 7) and 9 × 18 + 9 × 7.
Show your work
Practice Set · Part 4
The Distributive Property
Show what you know
Last check
These two come from Lesson 6.13. If they are shaky, that is the lesson to revisit — not this one.
- 12
Show what you knowExplain your thinking — Which expression is equivalent to 7(x + 3)?
- A7x + 21
- B7x + 3
- C7x + 10
- Dx + 21
Explain your choice.
- 13
From Lesson 6.13Explain your thinking — What is the prime factorization of 40?
- A2 × 2 × 2 × 5
- B2 × 20
- C4 × 10
- D5 × 8
How do you know?
- 14
From Lesson 6.13Which grid would NOT use exactly all 72 seed pods?
- A3 by 24
- B4 by 18
- C5 by 14
- D6 by 12
How do you know?
Be honest — this tells your teacher what to do next
| I can… | Not yet | Getting there | Got it |
|---|---|---|---|
| I can use the distributive property to expand and factor expressions, explain why the method works, and use it on a problem I have not seen before. | |||
| I can explain why it works: Expanding multiplies the outside factor by every term, and factoring pulls the GCF out… | |||
| 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