Mathematics content standards (Grade 8)
The Georgia Milestones Grade 8 Mathematics assessment samples the state's grade 8 content standards. Items ask you to reason across five connected strands: irrational numbers, expressions and equations, functions, geometry, and bivariate statistics. Because many questions embed math in context, track units and representations as carefully as you track computations.
What the standards emphasize
- The number system: classify values as rational or irrational, convert repeating decimals to fractions, and locate irrational square roots between consecutive integers.
- Expressions and equations: apply integer exponent rules, solve multi-step linear equations, graph proportional relationships, and solve systems of two linear equations by graphing, substitution, or elimination.
- Functions: decide whether a relation is a function, compare functions given as tables, graphs, equations, or verbal rules, and interpret rate of change and initial value.
- Geometry: apply the Pythagorean theorem and its converse, describe and perform rigid transformations, use angle relationships, and compute volumes of cylinders, cones, and spheres.
- Statistics: interpret scatter plots, informally fit a line, explain slope and intercept in context, and read two-way tables using relative frequencies.
Worked example
A gym costs $40 to join plus $25 per month. A second gym charges $70 to join plus $15 per month. After how many months are total costs equal?
Let m be the number of months. First gym: 40 + 25m. Second gym: 70 + 15m. Set equal: 40 + 25m = 70 + 15m. Subtract 15m: 40 + 10m = 70. Subtract 40: 10m = 30. Divide by 10: m = 3. Check: 40 + 25(3) = 115 and 70 + 15(3) = 115. The costs match at 3 months, $115 total.
Traps that cost marks
- Swapping slope and y-intercept when interpreting a graph: slope is the rate per unit; intercept is the starting value.
- Substituting the diameter for the radius in volume formulas.
- Treating a strong scatter-plot association as proof of causation.
- Forgetting that the converse of the Pythagorean theorem is what classifies a triangle as right, acute, or obtuse.
- Applying a transformation rule to the wrong coordinate, especially reflections over y = x.
- Mishandling negative exponents or dropping a negative sign during simplification.