Eighth-Grade Mathematics Standards

eighth-grade-mathEighth-grade students connect their understanding of rates and relationships to points on a line, using linear equations and functions to analyze and solve problems. They also learn about the Pythagorean Theorem. Here are a few examples of what your child will study throughout the year, questions to ask his or her teachers and tips for reinforcing math skills at home.

Number System

  1. Understand the difference between rational and irrational numbers; for example, rational numbers can be expressed as fractions and decimals, but irrational numbers can only be written as an unending decimal.
    Pi: (π = 3.14159265359…) is an irrational number because it is an unending decimal. A number such as 1.5 is rational because it can be written as a fraction:
    fractions

Expressions and Equations

  1. Work problems that involve radical numbers, including square roots and cube roots.
    2 + 2(√7)2
    = 2 + 2(7)
    = 2 + 14
    = 16
  2. Write and solve linear equations.
    5x + 3x = 8
    8x = 8
    x = 1
  3. Solve basic equations that use exponents.
    fractions

Functions

  1. Comprehend functions as rules that assign one input to one output and that can be expressed using tables, graphs and equations.
    X 0 1 2 2 3 4
    Y 1 2 1 3 0 5

    This is not a function because “2” is an X value more than once.

  2. Complete word problems that involve proportional relationships; be able to illustrate the solution using a graph.

Geometry

  1. Understand the Pythagorean Theorem and how it is used as an equation to solve problems.
    Q: pythagorean-theorem
    A: a2 + b2 = c2
    a2 + 42 = 52
    a2 + 16 = 25
    a2 = 9
    a = √9
    a = 3
  2. Gain knowledge of the difference between congruent and similar two-dimensional objects.
    Q: triangles
    A: These two triangles are similar triangles because the second triangle increases by a factor of 2.
    (6 × 2 = 12); (2 × 2 = 4)

Statistics and Probability

  1. Learn and use the best-fit line method to compare two values.
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