6.10 Small Group · Group 1
Second Practice Form · Re-Teach, Homework or Retake · Same Standard, New Problems
Divide Mixed Numbers · Mixed Number · Procedural Fluency · Real-World Applications
- A mixed number, like 3 1/2, has a whole part and a fraction part. Before you can divide, you change each mixed number into an improper fraction (top heavier than bottom). Then you use Keep, Change, Flip. We'll walk through a worked example, try one together, then you'll try a few with hints right there when you need them.
- Agent Chen has a 3 1/2-mile route cut into 1/4-mile segments. I want 3 1/2 ÷ 1/4.
- First I convert 3 1/2. Multiply the whole by the bottom: 3 × 2 = 6. Add the top: 6 + 1 = 7. So 3 1/2 = 7/2.
- Now Keep, Change, Flip: keep 7/2, change ÷ to ×, flip 1/4 to 4/1.
- Multiply: 7/2 × 4/1 = 28/2.
- Simplify: 28/2 = 14. So 3 1/2 ÷ 1/4 = 14 segments.
- Divide Mixed Numbers (Dividir números mixtos) — Change mixed numbers to improper fractions, then multiply by the reciprocal.
- Mixed Number (Número mixto) — A whole number plus a fraction, like 2 1/3.
- Improper Fraction (Fracción impropia) — A fraction where the top is bigger than or equal to the bottom, like 7/4.
- Convert (Convertir) — To change a number to a new form but keep the same value.
- Simplify (Simplificar) — To write a fraction with smaller numbers that names the same amount, like 2/4 = 1/2.
- Reciprocal (Recíproco) — A fraction turned upside down. You use it in keep-change-flip.
- A common mistake in Divide Mixed Numbers is dividing the whole-number parts and fraction parts separately instead of converting first — for example, treating 4 1/2 ÷ 1 1/2 as (4 ÷ 1) + (1/2 ÷ 1/2) = 5. Always convert each mixed number to one improper fraction first, then divide using Keep, Change, Flip: 4 1/2 ÷ 1 1/2 = 9/2 ÷ 3/2 = 9/2 × 2/3 = 3.
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1 MULTIPLE CHOICE
A baker has 2 1/4 cups of butter. Each batch of cookies needs 3/4 cup of butter. How many batches can the baker make?
- A3 batches
- B1 1/2 batches
- C2 batches
- D6 batches
✏️ Workspace & Solution Steps -
2 MULTIPLE CHOICE
Mission 1: The stakeout shift is 4 1/2 hours long. Each agent covers a 1 1/2-hour watch. How many agent watches fill one shift?
- A3
- B6
- C2 1/2
- D4 1/2
✏️ Workspace & Solution Steps -
3 MULTIPLE CHOICE
Mission 2: A surveillance route is 3 miles long, split into 1 1/2-mile patrol sections. How many sections are on the route?
- A2
- B1 1/2
- C4 1/2
- D3
✏️ Workspace & Solution Steps -
4 MULTIPLE CHOICE
Mission 3: There are 7 1/2 feet of caution tape to seal a crime scene. Each doorway needs 2 1/2 feet. How many doorways can be sealed?
- A3
- B5
- C2 1/2
- D10
✏️ Workspace & Solution Steps
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5 ERROR ANALYSIS
Spot the Common Mistake
- 1Problem:1 1/2 ÷ 3/4
- 2Convert:1 1/2 = 3/2
- 3Keep, Change, Flip:3/2 × 3/4
- 4Multiply:9/8 = 1 1/8
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation -
6 ERROR ANALYSIS
Level 2 Extension — The Rookie Detective's Mistake
- 1Problem:4 1/2 ÷ 1 1/2
- 2Divide the whole parts:4 ÷ 1 = 4
- 3Divide the fraction parts:1/2 ÷ 1/2 = 1
- 4Combine:4 + 1 = 5 watches
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation
Writing Task: Justify why your mathematical solution is accurate and complete.