Grade 8 math
Lessons commonly taught in grade 8, each with worked examples, practice problems, and complete solutions. Topics often span more than one grade, so you may see a lesson listed under a neighbouring grade too.
17 lessons · 17 standards
Algebra and Equations
- Domain and Range: The Inputs and Outputs of a Function
What domain and range mean, how to find them from a graph, a table or an equation, and why some inputs have to be excluded.
- Function Notation: What f(x) Actually Means
Understand f(x) as a name and an input rather than multiplication, how to evaluate it, and how to read statements like f(3) = 7 in context.
- How to Graph Linear Equations
Graph a line three ways — from slope-intercept form, from intercepts, or from a table — and understand why every point on the line is a solution.
- Linear vs Nonlinear Functions: How to Tell Them Apart
Four reliable tests for deciding whether a relationship is linear — from its equation, its table, its graph, or its rate of change.
- How to Solve Literal Equations and Rearrange Formulas
Rearrange a formula to solve for any variable using the same inverse operations you use on numbers, with worked examples from geometry, physics, and finance.
- How to Solve Multi-Step Equations
Solve multi-step equations by distributing, combining like terms, then undoing operations in reverse order, with worked examples and practice problems.
- How to Solve Multi-Step Inequalities
Solve multi-step inequalities by distributing, combining like terms, and undoing operations in reverse order, including when to flip the inequality sign.
- Point-Slope Form: Writing a Line from One Point
Learn point-slope form, why it is the slope formula rearranged, and how to use it to write a line's equation from a single point and a slope.
- The Quadratic Formula: How and Why It Works
Learn the quadratic formula, where it comes from, and how to use it to solve any quadratic equation, with worked examples and practice problems.
- Rate of Change: Slope With Units Attached
What average rate of change means, how it relates to slope, how to compute it from a table or a function, and how to read its units and sign.
- What Slope Is, and Why It Never Changes on a Line
Learn what slope measures, how to find it with rise over run and the slope formula, and why similar triangles guarantee it is the same everywhere on a line.
- Slope-Intercept Form: y = mx + b
Understand y = mx + b, what m and b each control, how to graph a line from it in two moves, and how to rewrite any linear equation into this form.
- Standard Form of a Linear Equation: Ax + By = C
What standard form is, when it beats slope-intercept form, how to convert between the two, and how to find the slope without rearranging.
- How to Solve Two-Step Equations
Solve two-step equations by undoing addition first and multiplication second, with worked examples, common mistakes, and practice problems with full solutions.
- Solving Equations with Variables on Both Sides
Solve equations with variables on both sides by collecting variable terms on one side, plus how to recognise no solution and infinitely many solutions.
- How to Write the Equation of a Line from Two Points
Find a line's equation from any two points: compute the slope, substitute into point-slope form, then simplify — with worked examples and full solutions.
- x-Intercepts and y-Intercepts: Finding Where a Line Crosses
Find the x- and y-intercepts of any equation by setting the other variable to zero, why that works, and what intercepts mean in a real situation.
Standards covered
- CCSS.MATH.CONTENT.7.EE.B.4a
- CCSS.MATH.CONTENT.8.EE.B.5
- CCSS.MATH.CONTENT.8.EE.B.6
- CCSS.MATH.CONTENT.8.EE.C.7a
- CCSS.MATH.CONTENT.8.EE.C.7b
- CCSS.MATH.CONTENT.8.F.A.1
- CCSS.MATH.CONTENT.8.F.A.3
- CCSS.MATH.CONTENT.HSA.CED.A.2
- CCSS.MATH.CONTENT.HSA.CED.A.4
- CCSS.MATH.CONTENT.HSA.REI.B.3
- CCSS.MATH.CONTENT.HSA.REI.B.4a
- CCSS.MATH.CONTENT.HSA.REI.B.4b
- CCSS.MATH.CONTENT.HSA.REI.D.10
- CCSS.MATH.CONTENT.HSF.IF.A.1
- CCSS.MATH.CONTENT.HSF.IF.A.2
- CCSS.MATH.CONTENT.HSF.IF.B.6
- CCSS.MATH.CONTENT.HSF.IF.C.7a