Math Mistakes:

more or less CCSS aligned.

Main menu

Skip to primary content
Skip to secondary content
  • About
  • Physics Mistakes

Category Archives: 8.EE.7

Backtracking

Posted on August 17, 2012 by mpershan | 5 Replies

What does the student understand, and what does she not? How would you help?

Posted in 8.EE.7, Solving Linear Equations.

I have nightmares about this one

Posted on July 20, 2012 by mpershan | 4 Replies

What aspect of solving linear equations is this student struggling with?  From the student’s point of view, why does the moves made seem like the right ones?

Are there any interesting things that you do to help students with linear equations? How do you make the right moves seem intuitive?

Posted in 8.EE.7, A-REI.3, Solving Linear Equations.

About

This site is about compiling, analyzing and discussing the mathematical errors that students make. Every day a new mistake is posted. The site is edited by Michael Pershan, a high school math teacher from NYC.

Submit a mistake

To keep the site going we need lots of interesting mistakes. To submit a picture of mathematical work, email mathmistakes@gmail.com

Categories

  • ►Elementary School (35)
    • Fractions (10)
    • Decimals (3)
    • Multiplication (4)
    • Place Value (3)
    • Subtraction (5)
    • Patterns (1)
    • Counting (1)
    • Addition (1)
    • ►Geometry (1)
      • Midpoint (0)
    • Money (1)
  • ►Geometry (24)
    • Isosceles Triangles (2)
    • Quadrilaterals (4)
    • Proofs (1)
    • Pythagorean Theorem (5)
    • Circles (1)
    • Similar Figures (2)
    • Right Triangles (3)
    • Equations of Parallel and Perpendicular Lines (1)
    • Distance Between Points (1)
  • ►Middle School (15)
    • Rates (1)
    • Converting Units (1)
    • Decimals (1)
    • Area (2)
    • Perimeter and Volume (1)
    • Exponents (2)
    • Rounding (1)
    • Expressions (1)
    • Geometry (1)
  • ►Algebra 1 (137)
    • exponents (20)
    • factoring (6)
    • ►linear functions (15)
      • horizontal and vertical lines (1)
      • slope (6)
    • Quadratics (6)
    • Radicals (4)
    • Solving Linear Equations (12)
    • Quadratic Functions (3)
    • Scientific Notation (1)
    • Graphing (8)
    • Simplifying expressions (3)
    • Negative Numbers (9)
    • Rational Expressions (5)
    • Solving Linear Inequalities (1)
    • Arithmetic (3)
    • Distributive Property (10)
    • ►Expressions (14)
      • Multiplying Polynomials (5)
    • Ratios and Proportions (3)
    • Solving for a Variable (1)
    • Systems of Equations (2)
  • ►Algebra 2 (38)
    • ►Functions (8)
      • Inverses (1)
    • logarithms (3)
    • Rational Expressions (3)
    • Radicals (1)
    • Quadratic Functions (4)
    • Complex Numbers (7)
    • Solving Trig Equations (1)
    • Vectors and Matrices (2)
    • Absolute Value (2)
    • Systems of Equations (2)
    • Exponents (1)
  • ►Trigonometry (21)
    • Law of Cosines (1)
    • Law of Sines (3)
    • Solving Trig Equations (0)
    • Trig Identities (10)
    • Inverse Trig Functions (1)
    • Arc Length (1)
    • Exact Values of Trig Functions (1)
    • Graphing Trig Functions (1)
  • ►Calculus (12)
    • Limits (3)
    • Derivatives (3)
    • Max/Min Problems (1)
    • Rates of change (1)
    • Tangent Lines (1)

Common Core Standards

  • ►Grade 1 (3)
    • ►Operations & Algebraic Thinking (1)
    • ►Number & Operations in Base 10 (2)
      • ►1.NBT.2 (1)
    • ►Measurement & Data (0)
    • ►Geometry (0)
  • ►Grade 2 (5)
    • ►Operations & Algebraic Thinking (1)
      • ►2.OA.1 (1)
    • ►Numbers & Operations in Base 10 (2)
    • ►Measurement & Data (2)
    • ►Geometry (0)
  • ►Grade 3 (9)
    • ►Operations and Algebraic Thinking (3)
      • ►3.OA.1 (2)
    • ►Numbers & Operations in Base 10 (2)
    • ►Numbers & Operations — Fractions (2)
      • ►3.NF.2 (2)
    • ►Measurement & Data (1)
    • ►Geometry (1)
  • ►Grade 4 (8)
    • ►Operations & Algebraic Thinking (0)
    • ►Numbers & Operations in Base 10 (3)
    • ►Numbers & Operations — Fractions (4)
    • ►Measurement & Data (0)
    • ►Geometry (0)
  • ►Grade 5 (12)
    • ►Operations & Algebraic Thinking (1)
    • ►Numbers & Operations in Base 10 (3)
      • ►5.NBT.3 (1)
    • ►Number & Operations — Fractions (5)
    • ►Measurement & Data (0)
    • ►Geometry (3)
  • ►Grade 6 (17)
    • ►Ratios & Proportional Relationships (2)
      • ►6.RP.3 (1)
    • ►The Number System (2)
    • ►Expressions & Equations (9)
    • ►Geometry (3)
    • ►Statistics & Probability (1)
  • ►Grade 7 (12)
    • ►Ratios & Proportional Relationships (1)
    • ►The Number System (9)
    • ►Expressions & Equations (1)
    • ►Geometry (1)
    • ►Statistics & Probability (0)
  • ▼Grade 8 (26)
    • ▼Expressions and Equations (21)
      • "Are there systems that have three solutions?"
      • (-2)^5 + (2)^0 = 0
      • Another pre-instruction survey, this time about polynomial multiplication
      • Combining like terms
      • Combining like terms...
      • Cross-multiplying or Cross-cancelling?
      • Diving into the Multiplying Polynomials Survey
      • Inconsistent Polynomial Multiplication
      • Khan Academy Potpourri
      • Slope and Division of Negative Numbers
      • Solving equations
      • Solving Simple Equations
      • Solving Systems Algebraically
      • Solving the Expression
      • The Distributive Property of Exponents
      • What do powers mean, again?
      • ▼8.EE.7 (2)
        • Backtracking
        • I have nightmares about this one
      • ►8.EE.1 (2)
      • ►8.EE.4 (1)
    • ►The Number System (2)
    • ►Functions (0)
    • ►Geometry (3)
    • ►Statistics & Probability (0)
  • ►High School: Number and Quantity (15)
    • ►The Real Number System (5)
      • ►N-RN.2 (1)
      • ►N.RN.1 (1)
    • ►Quantities* (0)
    • ►The Complex Number System (7)
      • ►N.CN.2 (1)
    • ►Vector and Matrix Quantities (2)
  • ►High School: Algebra (34)
    • ►Seeing Structure in Expressions (9)
      • ►A-SSE.2 (1)
    • ►Arithmetic with Polynomials and Rational Expressions (10)
    • ►Creating Equations* (2)
    • ►Reasoning with Equations and Inequalities (13)
      • ►A-REI.1 (1)
      • ►A-REI.3 (1)
      • ►A-REI.4 (1)
  • ►High School: Functions (52)
    • ►Interpreting Functions (7)
      • ►F-IF.7 (1)
    • ►Building Functions (9)
      • ►F-BF.1 (2)
    • ►Linear, Quadratic, and Exponential Models* (14)
    • ►Trigonometric Functions (17)
  • ►High School: Modeling (2)
  • ►High School: Geometry (11)
    • ►Congruence (1)
      • ►G.CO.10 (1)
    • ►Similarity, Right Triangles and Trigonometry (4)
      • ►G-SRT.10 (1)
    • ►Circles (1)
    • ►Expressing Geometric Properties with Equations (1)
      • ►G-GPE.2 (1)
    • ►Geometric Measurement and Dimension (3)
    • ►Modeling with Geometry (0)
  • ►High School: Statistics and Probability (5)
    • ►Interpreting Categorical and Quantitative Data (2)
    • ►Making Inferences and Justifying Conclusions (0)
    • ►Conditional Probability and the Rules of Probability (2)
    • ►Using Probability to Make Decisions (0)

Archives

  • RSS - Posts
  • RSS - Comments

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 100 other subscribers

© 2013 Math Mistakes:, all rights reserved.
Proudly powered by WordPress