6.NOS.1
Lesson 6-2-group2
🟣 Group 2 · Challenge & Extension
MASTERY CHECK
☐ Exceeds☐ Meets Target☐ Needs Practice
6.2 Small Group · Group 2
Tier 1 Extension · Non-Routine Synthesis · Misconception Traps · Rigorous CER Proofs
Divide Fractions · Dividend · Procedural Fluency · Reasoning & Critique
■ ADVANCED CONCEPT ANCHOR: Push further — How do I divide one fraction by another fraction?
1To divide fractions, multiply the first by the reciprocal of the second, then simplify. A mixed number has to become an improper fraction BEFORE that happens — and you can say why it is true, and where it would stop being true.
- You already can do this. So we go up a level, not up a number: find what is always true, show it a second way, and be ready to defend it with a reason instead of an answer.
2Worked Example — Watch me
- Agent Rivera has 3/4 pound and each portion is 1/8 pound. I want 3/4 ÷ 1/8.
- Keep 3/4. Change ÷ to ×. Flip the divisor 1/8 to its reciprocal 8/1.
- Multiply across: 3/4 × 8/1 = 24/4.
- Simplify: 24/4 = 6. So 3/4 ÷ 1/8 = 6. She can make 6 portions.
3Second Model — Try it together — then prove it
- Let's try 1/2 ÷ 1/4. Keep 1/2, change to ×, flip 1/4 to 4/1.
- Multiply: 1/2 × 4/1 = 4/2.
- Simplify: 4/2 = 2. So 1/2 ÷ 1/4 = 2.
- Now prove it: say why that move had to work at all — not just that it did.
- Sentence frame — convince a skeptic: "My method works because ___ . It would stop working if ___ ."
4Mathematical Word Bank
- Divide Fractions (Dividir fracciones) — Multiply the first fraction by the reciprocal of the second fraction.
- Dividend (Dividendo) — The total number being divided into equal groups (the number inside the division bracket).
- Divisor (Divisor) — The number of equal groups you are dividing into (the number outside the division bracket).
- Reciprocal (Recíproco) — A fraction turned upside down.
- Quotient (Cociente) — The answer when you divide.
- Simplify (Simplificar) — To write a fraction with smaller numbers that names the same amount, like 2/4 = 1/2.
5Watch out
- A common mistake in Divide Fractions is flipping the wrong fraction: students flip the dividend (the first fraction) instead of the divisor (the second fraction). For example, solving 3/4 ÷ 5/8 by flipping 3/4 to 4/3 and keeping 5/8 gives 4/3 × 5/8 = 20/24 = 5/6 — but only the divisor gets flipped. Keep 3/4, change ÷ to ×, and flip only the divisor 5/8 to its reciprocal 8/5: 3/4 × 8/5 = 24/20 = 6/5. Before you submit, check that the fraction you kept (the dividend) is still facing the same way it started.
SECTION 1
CONCEPTUAL UNDERSTANDING & VISUAL MODELS
[Visual Modeling]
-
1 FILL TABLE
Divide each pair of fractions using Keep, Change, Flip.
Problem Keep, Change, Flip Quotient 1/2 ÷ 1/6 3/4 ÷ 1/4 2/3 ÷ 1/3 5/8 ÷ 1/4 ✏️ Scratchpad / Reasoning -
2 MATCHING GAME
Match each fraction division to its quotient.
- 4/5 ÷ 2/5
- 3/4 ÷ 3/8
- 5/6 ÷ 1/3
- 2/3 ÷ 1/6
- 7/8 ÷ 1/4
- 1/2 ÷ 3/4
- A2
- B2
- C2 1/2
- D4
- E3 1/2
- F2/3
SECTION 2
COMPUTATION & PROCEDURAL FLUENCY
[Show Every Step]
-
3 MULTIPLE CHOICE
What is (3/4) ÷ (1/2)?
- A3/2
- B3/8
- C1/2
- D2/3
Write any whole number over 1Keep · Change · FlipMultiply acrossSimplify · label the units -
4 MULTIPLE CHOICE
What is (2/3) ÷ (4/9)?
- A3/2
- B8/27
- C2/3
- D9/4
Write any whole number over 1Keep · Change · FlipMultiply acrossSimplify · label the units -
5 MULTIPLE CHOICE
What is (5/6) ÷ (5/12)?
- A2
- B1/2
- C25/72
- D12/5
Write any whole number over 1Keep · Change · FlipMultiply acrossSimplify · label the units -
6 MULTIPLE CHOICE
What is (7/8) ÷ (1/4)?
- A7/2
- B7/32
- C1/2
- D4/7
Write any whole number over 1Keep · Change · FlipMultiply acrossSimplify · label the units
🗣️ MATHEMATICAL DISCOURSE & TALK MOVES
SMP.3 / Construct Viable Arguments
Group Discussion Prompt: How does your visual model justify your mathematical solution?
🗣️ Partner A:
Partner A: "I modeled this by identifying the relationship and..."
Partner A: "I modeled this by identifying the relationship and..."
👂 Partner B:
Partner B: "I agree with your step because the standard mathematical rule states..."
Partner B: "I agree with your step because the standard mathematical rule states..."
✍️ The Writing Revolution (TWR) · Sentence Expansion
Because · But · So
Complete each sentence stem to demonstrate precise mathematical reasoning:
BECAUSE
The mathematical model proves the solution because each step preserves quantitative equivalence.
BUT
An estimate provides a quick benchmark, but an exact proof is required for precision.
SO
The quantities follow the standard rule, so the final result is verified with certainty.
📐 CER MATHEMATICAL PROOF MATRIX (CER 2.0)
SMP.3 / Proof & Justification
Writing Task: Justify why your mathematical solution is accurate and complete.
C Claim
State your direct mathematical answer/claim with units.
E Evidence
Cite exact numbers, calculations, dimensions, or graph data.
R Reasoning
Explain the mathematical theorem, property, or definition connecting evidence to claim.