5.MD.C.5 Lesson 1-4-part2 Apply Day · Set B
MASTERY CHECK
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1.4 · Part II

Second Practice Form · Independent Application and Spiral Review

argument · conjecture

Interactive Workbench & Models →
Name: Date: Period: Learning Goal:
■ ADVANCED CONCEPT ANCHOR: 1.4 · Part II
1Math Practices: Mathematical Arguments & Justification
2The Structural Procedure
  1. State a clear claim or conjecture supported by calculations
  2. Use accurate units and vocabulary (e.g. cubic units for volume)
  3. Test with counterexamples to verify that the rule holds true every time
3Mathematical Word Bank
  • argument (argumento) — A chain of reasons — equations, drawings, or words — used to defend your thinking.
  • conjecture (conjetura) — A mathematical statement you believe is true but have not yet proven.
  • counterexample (contraejemplo) — A single example that shows a statement is not always true.
  • volume (volumen) — The amount of space a solid figure takes up, measured in cubic units.
  • cubic unit (unidad cúbica) — A cube with edges 1 unit long — the unit used to measure volume.
4Watch out
  • Reporting volume without cubic units — saying the garden needs '48 feet' of soil, which is a length, or '48 square feet', which is an area.
SECTION 1 CONCEPTUAL UNDERSTANDING & VISUAL MODELS [Visual Modeling]
  1. 1 MULTIPLE CHOICE

    Which statement is a CONJECTURE?

    1. A“I think the two jumbo boxes hold more cereal than the three large boxes.”
    2. B“8 × 3 × 10 = 240.”
    3. C“Volume is measured in cubic units.”
    4. D“Yuzuki bought cereal.”
    ✏️ Workspace & Solution Steps
  2. 2 MULTIPLE CHOICE

    Which statement is a CONJECTURE?

    1. A“I think the two jumbo boxes hold more cereal than the three large boxes.”
    2. B“8 × 3 × 10 = 240.”
    3. C“Volume is measured in cubic units.”
    4. D“Yuzuki bought cereal.”
    ✏️ Workspace & Solution Steps
SECTION 2 REAL-WORLD CONTEXTS & PROBLEM SOLVING [Applications]
  1. 3 MULTIPLE CHOICE

    An egg muffin is about 60 calories. A plate holds 4 egg muffins. About how many calories are on the plate?

    1. AAbout 240
    2. BAbout 64
    3. CAbout 15
    4. DAbout 600
    ✏️ Workspace & Solution Steps
  2. 4 MULTIPLE CHOICE

    A large cereal box is 8 in long, 3 in wide, and 10 in tall. What is its volume?

    1. A240 cubic inches
    2. B21 cubic inches
    3. C80 cubic inches
    4. D240 square inches
    Formula
    Put the numbers in
    Work it out
    Answer with its unit
  3. 5 MULTIPLE CHOICE

    Each jumbo box holds 400 cubic inches. How much do TWO jumbo boxes hold?

    1. A800 cubic inches
    2. B402 cubic inches
    3. C200 cubic inches
    4. D4,000 cubic inches
    ✏️ Workspace & Solution Steps
SECTION 3 MATHEMATICAL WRITING & ERROR ANALYSIS [Reasoning & Critique]
  1. 6 OPEN RESPONSE

    A student recommends the three large boxes because the cereal stays fresher — each box is open for less time. Is this argument convincing? Explain.

    ✏️ Mathematical Justification & Response
  2. 7 OPEN RESPONSE

    Write TWO arguments for the same recommendation about Yuzuki's cereal — one using equations, one using only words. Then say which you think would convince a classmate more, and why.

    ✏️ Mathematical Justification & Response
📐 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.
Student Mastery Self-Assessment:
1 · Need More Support
2 · Getting Closer
3 · Got It / Solid
4 · Master / Can Teach It