6.AT.8 Lesson 8-2-part2 Apply Day · Set B
MASTERY CHECK
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8.2 · Part II

Second Practice Form · Independent Application and Spiral Review

Solve One-Step Addition and Subtraction Equations · Equation

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Name: Date: Period: Learning Goal:
■ ADVANCED CONCEPT ANCHOR: 8.2 · Part II
1Solving Addition & Subtraction Equations
2The Structural Procedure
  1. Identify operation on variable
  2. Use inverse operation: subtract to undo addition; add to undo subtraction
  3. Property of Equality: do same operation to both sides
3Mathematical Word Bank
  • Solve One-Step Addition and Subtraction Equations (Resolver ecuaciones de suma y resta de un paso) — Use one inverse addition or subtraction operation to isolate the variable.
  • Equation (Ecuación) — A math sentence with an equal sign showing both sides are the same.
  • Inverse operation (Operación inversa) — Two math actions that undo each other, like × and ÷.
  • Isolate (Despejar) — To get the letter by itself on one side.
  • Solution (Solución) — A number that makes the equation or inequality true.
  • One-step equation (Ecuación de un paso) — An equation you can solve in a single step using one inverse operation.
4Watch out
  • A common mistake is applying the same operation instead of the inverse — for example, solving x − 7 = 15 by subtracting 7 from both sides (getting the wrong x = 8) instead of adding 7 to both sides (the correct x = 22). Another common mistake is doing the inverse operation to only one side, like solving x + 6 = 14 by subtracting 6 from the left but forgetting the right side. Before you submit, name the operation shown in the equation, choose its inverse, apply it to BOTH sides, and check by substituting your answer back into the original equation.
SECTION 1 REAL-WORLD CONTEXTS & PROBLEM SOLVING [Applications]
  1. 1 MULTIPLE CHOICE

    Which value of n is the solution of n − 18 = 27?

    1. An = 45
    2. Bn = 9
    3. Cn = 27
    4. Dn = 18
    ✏️ Workspace & Solution Steps
  2. 2 MULTIPLE CHOICE

    Solve: x + 9 = 15

    1. Ax = 6
    2. Bx = 24
    3. Cx = 9
    4. Dx = 15
    ✏️ Workspace & Solution Steps
  3. 3 MULTIPLE CHOICE

    Solve: y − 7 = 20

    1. Ay = 27
    2. By = 13
    3. Cy = 7
    4. Dy = 140
    ✏️ Workspace & Solution Steps
  4. 4 MULTIPLE CHOICE

    Solve: n + 15 = 42

    1. An = 27
    2. Bn = 57
    3. Cn = 15
    4. Dn = 42
    ✏️ Workspace & Solution Steps
SECTION 2 MATHEMATICAL WRITING & ERROR ANALYSIS [Reasoning & Critique]
  1. 5 OPEN RESPONSE

    A detective solved x + 25 = 60 and got x = 35. Another detective solved y − 25 = 60 and got y = 35. Are both correct? Explain using inverse operations and check each answer.

    ✏️ 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