Lesson 6.11Fraction Division Problem Solving
Set B · Version ASecond form · supported practice
Learning target I can solve real-world problems by deciding whether the question asks how many groups fit or how much is in one group, writing a fraction division equation, and checking the solution by multiplying.
Why This Matters Agent Torres is closing the biggest case of the year. She has 2/3 of a gallon of fingerprint dust left and each test uses 1/6 of a gallon. Before the evidence expires, she needs to figure out exactly how many tests she can run. Can you write the equation and solve it?
RememberFraction Division Problem Solving
Fraction Division Word Problems. Formula: Total Amount ÷ Group Size = Number of Groups In a word problem, first decide what the question asks: how many groups fit (total ÷ size of each group) or how much is in one group (total ÷ number of groups). The total amount is the dividend and the other number is the divisor. Write the equation, solve it with a model, common denominators, or by multiplying by the reciprocal, then check by multiplying the quotient by the divisor.
- Identify the Dividend (total amount being split or shared).
- Identify the Divisor (size of each group or part).
- Divide: Total ÷ Size = Number of Groups (or Total ÷ Groups = Size per Group)
Words: Model (Modelo)Equation (Ecuación)Solution (Solución)Reasonableness (Razonabilidad)Inverse operations (Operaciones inversas)
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1Circle the letter of the best answer. Show how you know.
A forensic chemist has 5/6 of a liter of testing solution. Each DNA test requires 1/12 of a liter. She needs to figure out how many tests she can run before the solution runs out. Which equation matches the problem?
- A1/12 ÷ 5/6 = t
- B5/6 ÷ 1/12 = t
- C5/6 × 1/12 = t
- D5/6 + 1/12 = t
Show your work
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2Circle the letter of the best answer. Show how you know.
What is 2 1/2 ÷ 1/2?
- A1 1/4
- B2 1/4
- C4
- D5
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3Circle the letter of the best answer. Show how you know.
What is 1 1/2 ÷ 3/4?
- A1 1/8
- B2
- C3/4
- D1/2
Show your work -
4Circle the letter of the best answer. Show how you know.
What is 3 1/2 ÷ 1/4?
- A3 1/8
- B7/8
- C13/4
- D14
Show your work
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5Circle the letter of the best answer. Show how you know.
Three agents share 3/4 pound of casting clay equally. How much clay does each agent get? (3/4 ÷ 3 asks how much is in one share.)
- A2 1/4 pounds
- B4 pounds
- C3 3/4 pounds
- D1/4 pound
Hint Is each share more or less than the 3/4 pound you started with?
Show your work -
6Circle the letter of the best answer. Show how you know.
Convert 3 2/5 to an improper fraction.
- A6/5
- B15/5
- C17/5
- D32/5
Rewrite each fractionWork it outSimplify- 1Same size piecesCommon denominator first.
- 2OperateOnly then add or subtract.
- 3SimplifyDivide out common factors.
Explain your thinkingHow do you decide which value is the dividend and which is the divisor in a word problem?
Sentence starter The total amount is the ___ because it is being split into groups. The size of each group is the ___ because we are dividing by that amount.
Lesson 6.11Fraction Division Problem Solving
Set B · Version BSecond form · core practice
Learning target I can solve real-world problems by deciding whether the question asks how many groups fit or how much is in one group, writing a fraction division equation, and checking the solution by multiplying.
Why This Matters Agent Torres is closing the biggest case of the year. She has 2/3 of a gallon of fingerprint dust left and each test uses 1/6 of a gallon. Before the evidence expires, she needs to figure out exactly how many tests she can run. Can you write the equation and solve it?
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1Write the name of the correct group on each line.
Room 3 — Sort the Clues: Each safe opens only if you pick the clues that need fraction DIVISION. Sort each clue into the correct lock.
- A roll of crime-scene tape is 3/5 mile long, cut into 1/10-mile strips. How many strips? (3/5 ÷ 1/10)
- A footprint trail is 2/3 mile long with markers every 1/12 mile. How many markers? (2/3 ÷ 1/12)
- Each evidence bag weighs 1/4 pound. The detective grabs 4 bags. What is the total weight? (1/4 × 4)
- A report is 3/8 page long. Torres reads half of it. How much did she read? (3/8 × 1/2)
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2Write the letter of the matching item on each line.
Room 4 — Match the Lock: Drag each word problem to the division equation that unlocks it.
- A 4/5-yard cord is cut into 1/10-yard fuses for the alarm.
- A 1/2-gallon jug of luminol is poured into 1/8-gallon sprayers.
- A 3/4-mile escape route is split into 3/8-mile sprints.
- A 5/6-liter sample is divided into 1/12-liter test tubes.
- A4/5 ÷ 1/10 = 8
- B1/2 ÷ 1/8 = 4
- C3/4 ÷ 3/8 = 2
- D5/6 ÷ 1/12 = 10
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3Circle the letter of the best answer. Show how you know.
A forensic chemist has 5/6 of a liter of testing solution. Each DNA test requires 1/12 of a liter. She needs to figure out how many tests she can run before the solution runs out. 5/6 ÷ 1/12 = ?
- A2
- B5/72
- C10
- D12
Show your work -
4Circle the letter of the best answer. Show how you know.
A forensic chemist has 5/6 of a liter of testing solution. Each DNA test requires 1/12 of a liter. She needs to figure out how many tests she can run before the solution runs out. Is 10 tests a reasonable answer?
- ANo — the answer should be less than 1
- BYes — each test uses far less than the total, so the answer should be well above 1
- CNo — you cannot divide fractions
- DYes — because 10 is a round number
Show your work -
5Circle the letter of the best answer. Show how you know.
Room 1 — Evidence Locker: Agent Torres has 7/8 pound of casting clay to lift footprints. Each cast uses 1/8 pound. How many casts can she make to unlock the door?
- A1/7
- B6
- C7
- D8
Rewrite each fractionWork it outSimplify -
6Circle the letter of the best answer. Show how you know.
Room 2 — Surveillance Map: A suspect's trail is 5/6 of a mile. Hidden checkpoints are spaced every 1/6 of a mile. How many checkpoints are on the trail?
- A1/5
- B4
- C5
- D6
Rewrite each fractionWork it outSimplify