Practice Set · Part 1
Divide Whole Numbers by Fractions
Pick up where we left off
Where we left off
Our goal: With my small group, I can divide a whole number by a fraction by multiplying by the reciprocal — one step at a time, with support.
The big idea: Dividing by a fraction is the same as multiplying by its reciprocal (the fraction flipped over).
Model to copy — Watch me
- Agent Park has 4 pounds of powder and each bag holds 1/2 pound. I want 4 ÷ 1/2.
- Keep the 4. Change ÷ to ×. Flip 1/2 to make 2/1, which is just 2.
- Now I multiply: 4 × 2 = 8.
- So 4 ÷ 1/2 = 8. He can fill 8 bags. That makes sense: each pound fills 2 bags, and 4 pounds × 2 = 8.
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.
Let's try together: Let's try 3 ÷ 1/4 together. What do we keep? The 3. Change ÷ to ×, then flip 1/4 to 4/1, which is 4. Multiply: 3 × 4 = 12. So 3 ÷ 1/4 = 12.My first step is ___ , because the problem asks for ___ .
Show your work - 2
Warm restartWhich property is shown? 7 × 5 = 5 × 7
- ACommutative Property
- BAssociative Property
- CIdentity Property
- DDistributive Property
- 3
Warm restartWhich property is shown? (2 + 9) + 1 = 2 + (9 + 1)
- AAssociative Property
- BCommutative Property
- CIdentity Property
- DDistributive Property
- 4
Warm restartWhich grouping makes 4 × 25 × 7 easiest to multiply mentally?
- A(4 × 25) × 7
- B(25 × 7) × 4
- C4 × (25 + 7)
- D(4 + 25) × 7
Practice Set · Part 2
Divide Whole Numbers by Fractions
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 through10 ÷ 1/4 = ?
- A2.5
- B14
- C40
- D4
Why is that the answer?
I chose ___ because ___ .
- 6
Think it throughWhat is the reciprocal of 1/4?
- A4
- B1/4
- C−1/4
- D1/2
How do you know?
I chose ___ because ___ .
- 7
Think it throughA student answered 2.5. What did they do wrong?
- AThey divided by 4 instead of by 1/4
- BThey multiplied by 4
- CThey added 1/4
- DThey used the wrong rope length
Explain your thinking.
I chose ___ because ___ .
- 8
Back to the modelWhy does 3 ÷ 1/4 = 12? How does the number line show this?
3 ÷ 1/4 = 12 because it takes ___ jumps of ___ to get from 0 to ___.
Practice Set · Part 3
Divide Whole Numbers by Fractions
Words and reasoning
Word bank · Banco de palabras
Use the words
Fill each blank with a word from the bank.
- Multiply the whole number by the ___ of the fraction.
- A counting number like 0, 1, 2, or 3 with no fraction or decimal part is a ___.
- A number that shows part of a whole, like 3/4, is a ___.
- The fraction you get by flipping a fraction upside down is its ___.
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 Divide Whole Numbers by Fractions is doing 'Keep, Change' but skipping the 'Flip' — students multiply by the divisor as it is instead of by its reciprocal. - 10
Say moreHow does 'Keep, Change, Flip' turn 6 ÷ 1/3 into a multiplication problem?
I keep ___, change the sign to ___, and flip ___ to ___.
- 11
Change one numberGo back to Part 1 and pick one problem you already solved. Change one number in it, then solve your new version. Show every step.
If ___ changed to ___ , then ___ .
Show your work
Practice Set · Part 4
Divide Whole Numbers by Fractions
Show what you know
Last check
These two come from Lesson 6.8. If they are shaky, that is the lesson to revisit — not this one.
- 12
Show what you knowQuick check — you've got this: What is 9 ÷ 1/3?
- A27
- B3
- C9/3
- D1/27
Explain your choice.
I know it is ___ because ___ .
- 13
From Lesson 6.8Quick check — you've got this: Which property is shown? (8 + 5) + 2 = 8 + (5 + 2)
- AAssociative Property
- BCommutative Property
- CIdentity Property
- DDistributive Property
- 14
From Lesson 6.8What is 4 × 17 × 25?
- A1,700
- B170
- C425
- D1,000
Be honest — this tells your teacher what to do next
| I can… | Not yet | Getting there | Got it |
|---|---|---|---|
| I can divide a whole number by a fraction by multiplying by the reciprocal — one step at a time, with support. | |||
| I can explain why it works: Dividing by a fraction is the same as multiplying by its reciprocal (the fraction flipped over). | |||
| I can talk through each step out loud using a sentence frame and the lesson's key words. |
One question I want to ask my group next time