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Kentucky Standards

Kentucky 8th Grade Math Standards

All 27 Kentucky math standards for 8th grade, each explained in plain English. The official wording is in Kentucky Department of Education's document, linked at the end of this page.

27 standards

The Number System

2 standards
KY.8.NS.1
Explain that every number has a decimal form, that rational numbers end or repeat as decimals, and that numbers whose decimals do neither are irrational.
KY.8.NS.2
Estimate irrational numbers with nearby rational values to compare them, place them on a number line, and estimate expressions, like √2 is about 1.4.

Expressions and Equations

8 standards
KY.8.EE.1
Use exponent rules with integer exponents to rewrite number expressions, like 3² × 3⁻⁵ = 3⁻³ = 1/27.
KY.8.EE.2
Use square and cube root symbols to solve equations like x² = 49 or x³ = 8, find roots of small perfect squares and cubes, and know those roots are rational.
KY.8.EE.3
Estimate very large or very small amounts as a single digit times a power of 10, and tell how many times bigger one is, like 7 × 10⁹ is about 20 times 3 × 10⁸.
KY.8.EE.4
Calculate with numbers in scientific notation, mixing in decimals, choose sensible units for very large or small measurements, and read scientific notation shown by calculators.
KY.8.EE.5
Graph proportional relationships, read the unit rate as the slope, and compare two proportional relationships shown in different ways, like a table and an equation.
KY.8.EE.6
Use similar triangles to show a nonvertical line has the same slope between any two points, and know y = mx for lines through the origin and y = mx + b otherwise.
KY.8.EE.7
Solve one-variable linear equations with fractions, parentheses and like terms, and tell whether an equation has one solution, none or infinitely many.
Common Core 8.EE.7
KY.8.EE.8
Solve pairs of linear equations by substitution or inspection, see the solution as where the graphs cross with one, none, or infinitely many, and use them in word problems.

Functions

5 standards
KY.8.F.1
Know that a function gives exactly one output for each input, and that its graph is the set of all its input-output pairs.
Common Core 8.F.1
KY.8.F.2
Compare features of two functions shown in different ways, like an equation and a table, such as which has the greater rate of change.
KY.8.F.3
Explain why an equation in the form y = mx + b gives a linear function that graphs as a straight line, and identify and offer examples of nonlinear functions whose graphs curve, like y = x².
KY.8.F.4
Build a linear function for a situation, finding its rate of change and starting value from a description, two points, a table, or a graph, and explain what they mean.
KY.8.F.5
Describe how two quantities relate by reading a graph, like where it rises or falls, and sketch a graph that matches a described situation.

Geometry

9 standards
KY.8.G.1
Test with experiments that rotations, reflections, and translations keep lines as lines, keep segment lengths and angle measures, and keep parallel lines parallel.
KY.8.G.2
Know that two figures are congruent when one can be moved onto the other by slides, turns and flips, and describe the moves that do it.
Common Core 8.G.2
KY.8.G.3
Describe what happens to a figure's coordinates when it is slid, turned, flipped or scaled up or down.
Common Core 8.G.3
KY.8.G.4
Know that two figures are similar when slides, turns, flips and a resize can map one onto the other, and describe the sequence that does it.
Common Core 8.G.4
KY.8.G.5
Give informal reasons for facts about triangle angle sums and exterior angles, angles formed by parallel lines and a transversal, and triangle similarity from two matching angles.
KY.8.G.6
Explain a proof that a² + b² = c² in every right triangle, and that a triangle whose sides fit that rule must be a right triangle.
Common Core 8.G.6
KY.8.G.7
Use the Pythagorean theorem to find a missing side of a right triangle in real problems, flat or in three dimensions, like the diagonal of a box.
Common Core 8.G.7
KY.8.G.8
Find the distance between two points on a coordinate grid by treating it as the long side of a right triangle.
Common Core 8.G.8
KY.8.G.9
Use volume and surface area formulas for cones, cylinders, and spheres to solve real-life and math problems, like how much a cone-shaped cup holds.

Statistics and Probability

3 standards
KY.8.SP.1
Make and read scatter plots of paired number data and describe patterns like clusters, outliers, positive or negative association, and linear or nonlinear trends.
KY.8.SP.2
Know that straight lines often model how two variables relate, fit a line by eye to a scatter plot with a linear trend, and judge how close the points fall.
KY.8.SP.3
Use the equation of a fitted line to solve problems about paired data and explain what its slope and intercept mean, like each extra hour of study adding 5 points.

The official Kentucky documents

The plain-English lines on this page are EMStudio's own explanations of Kentucky's standards, not the official wording, which Kentucky Department of Education publishes in the documents above. Codes and strand names identify each standard.