6.NOS.3 Lesson 2-11-part2 Apply Day · Set B
MASTERY CHECK
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2.11 · Part II

Second Practice Form · Independent Application and Spiral Review

Add and Subtract Decimals · Decimal

Interactive Workbench & Models →
Name: Date: Period: Learning Goal:
■ ADVANCED CONCEPT ANCHOR: 2.11 · Part II
1Adding & Subtracting Decimals
2The Structural Procedure
  1. Line up the decimal points vertically by place value
  2. Insert placeholder zeros so each number has the same number of decimal digits
  3. Add or subtract right-to-left, regrouping as needed, and drop decimal straight down
3Mathematical Word Bank
  • Add and Subtract Decimals (Sumar y restar decimales) — Combine or find the difference between decimals by lining up equal place values.
  • Decimal (Decimal) — A number with a dot, like 0.5, that shows a part less than one.
  • Place value (Valor posicional) — What a digit is worth based on where it sits in a number.
  • Tenths (Décimas) — The first spot after the decimal point. It shows parts out of 10.
  • Hundredths (Centésimas) — The second spot after the decimal point. It shows parts out of 100.
  • Annex zeros (Agregar ceros) — Adding zeros at the end of a decimal so numbers line up evenly.
4Watch out
  • A common mistake in Add and Subtract Decimals is lining up the last digits (the right edges) of each number instead of lining up the decimal points — for example, adding 8.3 and 2.45 as if the 3 and the 5 belong in the same column. Before you add or subtract, add zeros so every number has the same number of decimal places (write 8.3 as 8.30), then check that the decimal points sit directly above one another.
SECTION 1 COMPUTATION & PROCEDURAL FLUENCY [Show Every Step]
  1. 1 MULTIPLE CHOICE

    Find 12.4 + 3.75.

    1. A16.15
    2. B15.15
    3. C16.79
    4. D4.99
    Line up the place values
  2. 2 MULTIPLE CHOICE

    What is 14.6 + 3.85?

    1. A18.45
    2. B18.35
    3. C17.45
    4. D18.55
    Line up the place values
  3. 3 MULTIPLE CHOICE

    What is 9.05 + 4.7?

    1. A13.75
    2. B13.12
    3. C14.75
    4. D13.57
    Line up the place values
SECTION 2 REAL-WORLD CONTEXTS & PROBLEM SOLVING [Applications]
  1. 4 MULTIPLE CHOICE

    What is 20.3 − 7.48?

    1. A12.82
    2. B13.82
    3. C12.92
    4. D12.18
    Line up the place values
SECTION 3 MATHEMATICAL WRITING & ERROR ANALYSIS [Reasoning & Critique]
  1. 5 OPEN RESPONSE

    A runner's lap times are 2.45 minutes, 2.6 minutes, and 2.38 minutes. Her personal record is 7.5 minutes total. Did she beat her record? Show all your work with decimal alignment and explain.

    ✏️ 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