4:00
Pre-Algebra
Intro
Place Value & Decimals
Why the same digit is worth different amounts depending on where it sits.
Every algebra and geometry topic,
explained two ways
Pre-Algebra, Algebra 1, Geometry and Algebra 2. Each topic has a hand-picked video, a plain-English explanation, a rigorous one, a worked example, and unlimited practice problems.
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173
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across 4 courses
173 topics
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173 topics
4:00
9:53
Pre-Algebra
Intro
Factors & Multiples
Two words that get mixed up constantly, and the difference in one sentence.
11:28
Pre-Algebra
Intro
Prime Factorization
Breaking any number into the prime building blocks that only it has.
15:25
Pre-Algebra
Intro
GCF & LCM
The biggest thing that divides both, and the smallest thing they both divide.
5:20
Pre-Algebra
Intro
Order of Operations (PEMDAS)
Why 2 + 3 × 4 is 14 and not 20, and the order every calculator agrees on.
5:39
Pre-Algebra
Intro
Practice ready
Integers & Absolute Value
Negative numbers on the number line, and what the bars around a number really mean.
12:54
Pre-Algebra
Intro
Adding & Subtracting Integers
The sign rules, and the one reframing that makes them stop being rules.
5:32
Pre-Algebra
Intro
Multiplying & Dividing Integers
Why a negative times a negative is positive, not just that it is.
3:02
Pre-Algebra
Intro
Practice ready
Introduction to Exponents
Repeated multiplication, and the two exponents that look strange at first.
5:36
Pre-Algebra
Intro
Practice ready
Square Roots & Perfect Squares
Undoing a square, and why √ always hands back the positive answer.
3:34
Pre-Algebra
Intro
Equivalent Fractions & Simplifying
Different names for the same amount, and how to find the simplest one.
7:42
Pre-Algebra
Intro
Comparing & Ordering Fractions
Three reliable ways to tell which fraction is bigger.
7:23
Pre-Algebra
Core
Practice ready
Adding & Subtracting Fractions
Why you need a common denominator here but not when multiplying.
5:06
Pre-Algebra
Intro
Multiplying Fractions
The easiest fraction operation, and why the answer gets smaller.
9:35
Pre-Algebra
Core
Dividing Fractions
Keep, change, flip — and the reason it is not an arbitrary trick.
4:26
Pre-Algebra
Intro
Mixed Numbers & Improper Fractions
Converting between the two forms, and which one to use when.
3:32
Pre-Algebra
Core
Fractions, Decimals & Percents
One quantity, three costumes, and how to switch between them fast.
4:45
Pre-Algebra
Intro
Operations with Decimals
Where the decimal point goes in each of the four operations.
14:13
2:31
Pre-Algebra
Intro
Practice ready
Unit Rates
Making prices and speeds comparable by putting everything per one.
4:12
Pre-Algebra
Core
Practice ready
Proportions & Cross Multiplication
Two equal ratios, and the fastest way to find the missing piece.
5:22
Pre-Algebra
Core
Scale Drawings & Similar Figures
Same shape, different size, and what happens to area when you scale.
12:44
Pre-Algebra
Core
Percent of a Number
Tips, discounts, and tax without reaching for a calculator every time.
11:23
Pre-Algebra
Core
Percent Increase & Decrease
Measuring change against where it started, not where it ended.
22:06
Pre-Algebra
Core
Simple Interest
I = Prt, the formula behind loans, and how it differs from compounding.
6:55
Pre-Algebra
Intro
Variables & Expressions
What a letter is doing in a maths problem, and how to read one.
13:55
Pre-Algebra
Intro
Evaluating Expressions
Substituting a value for a variable without losing signs along the way.
4:32
Pre-Algebra
Core
Combining Like Terms
Which terms can be added together, and which only look like they can.
7:53
Pre-Algebra
Core
The Distributive Property
Multiplying across a sum, and the sign mistake that costs the most marks.
4:38
Pre-Algebra
Core
Practice ready
One-Step Equations
Undoing a single operation, and why you must do it to both sides.
5:12
Pre-Algebra
Core
Practice ready
Two-Step Equations
Unwrapping in reverse order — why the constant comes off first.
4:41
Pre-Algebra
Core
Practice ready
Writing Equations from Words
Turning a sentence into algebra — the step most word problems actually fail at.
6:24
Pre-Algebra
Core
Practice ready
Introduction to Inequalities
Solving like an equation, with one rule that has no equation equivalent.
5:39
Pre-Algebra
Intro
Practice ready
The Coordinate Plane
Axes, quadrants, and reading an ordered pair the right way round.
2:44
Pre-Algebra
Intro
Practice ready
Graphing from a Table
Turning a rule into points, and points into a line.
8:47
Pre-Algebra
Core
Practice ready
Slope as Rate of Change
Steepness as a number, and what it means outside of maths class.
9:53
Pre-Algebra
Core
Direct Variation
The special linear relationship that always passes through the origin.
7:07
Pre-Algebra
Intro
Angles & Parallel Lines
Angle pairs that are equal, angle pairs that add to 180, and how to tell.
4:28
Pre-Algebra
Intro
Triangles & Angle Sums
Why every triangle's angles add to 180°, and the polygon version of the rule.
8:25
17:19
Pre-Algebra
Core
Circles: Circumference & Area
Two formulas that look alike and get swapped constantly.
8:07
Pre-Algebra
Core
Volume & Surface Area
Filling a solid versus wrapping it, and the formulas for each.
4:34
Pre-Algebra
Core
The Pythagorean Theorem
a² + b² = c², the single most reused formula in all of maths.
43:51
11:37
Pre-Algebra
Intro
Mean, Median, Mode & Range
Four summaries of a data set, and when the average lies.
5:25
10:01
9:05
Pre-Algebra
Core
The Counting Principle
Multiplying choices to count possibilities without listing them.
5:54
Algebra 1
Intro
The Real Number System
Naturals, integers, rationals, irrationals — and which box a number lives in.
24:45
Algebra 1
Intro
Properties of Real Numbers
Commutative, associative, distributive, identity, inverse — the rules that justify every step.
9:43
Algebra 1
Core
Practice ready
Laws of Exponents
Multiply means add, divide means subtract, power of a power means multiply.
12:37
Algebra 1
Core
Practice ready
Negative & Zero Exponents
What a negative exponent actually means, and why it is not a negative answer.
10:27
Algebra 1
Core
Practice ready
Scientific Notation
Writing very large and very small numbers without counting zeros.
3:09
Algebra 1
Core
Practice ready
Simplifying Radicals
Pulling perfect squares out from under the root sign.
8:58
Algebra 1
Core
Practice ready
Multi-Step Equations
Simplify each side first, then isolate — in that order.
6:45
Algebra 1
Core
Practice ready
Variables on Both Sides
Getting every x onto one side, and what it means when they all disappear.
5:36
Algebra 1
Core
Practice ready
Equations with Fractions
Clear every denominator in one move and never work with fractions again.
4:55
Algebra 1
Core
Practice ready
Literal Equations
Solving a formula for one letter when everything else stays symbolic.
13:12
Algebra 1
Advanced
Practice ready
Absolute Value Equations
Why these usually have two answers, and when they have none.
30:44
Algebra 1
Core
Practice ready
Solving Linear Inequalities
Everything from equations carries over, except one rule.
11:45
Algebra 1
Advanced
Practice ready
Compound Inequalities
AND means overlap, OR means everything either one covers.
13:12
Algebra 1
Advanced
Practice ready
Absolute Value Inequalities
Less than gives a sandwich, greater than gives two pieces.
10:54
Algebra 1
Core
Practice ready
Relations & Functions
The one rule that decides whether a relation is a function.
11:49
12:51
7:31
Algebra 1
Core
Practice ready
Interpreting Function Graphs
Reading intercepts, increases, maximums and meaning off a picture.
7:06
Algebra 1
Core
Practice ready
The Slope Formula
Computing steepness from two points without a graph.
8:59
Algebra 1
Core
Practice ready
Slope-Intercept Form
y = mx + b, the form you can graph without any work.
3:58
Algebra 1
Core
Practice ready
Point-Slope Form
The fastest way to write a line's equation from a point and a slope.
3:23
Algebra 1
Core
Practice ready
Standard Form & Intercepts
Ax + By = C, and the two-point shortcut for graphing it.
9:13
Algebra 1
Core
Practice ready
Parallel & Perpendicular Lines
Same slope, or negative reciprocal slopes.
8:03
Algebra 1
Advanced
Practice ready
Graphing Linear Inequalities
A boundary line plus a shaded half-plane.
3:18
Algebra 1
Advanced
Scatter Plots & Line of Best Fit
Finding a trend in messy data, and the limits of trusting it.
8:30
Algebra 1
Core
Practice ready
Solving Systems by Graphing
The intersection point, and what parallel or identical lines mean.
4:38
Algebra 1
Core
Practice ready
The Substitution Method
Best when one variable is already alone, or easy to isolate.
10:20
12:44
Algebra 1
Advanced
Practice ready
Systems Word Problems
Two unknowns, two facts, and a reliable setup routine.
10:56
17:52
Algebra 1
Core
Adding & Subtracting Polynomials
Combining like terms, with one sign trap when subtracting.
6:25
Algebra 1
Core
Practice ready
Multiplying Binomials (FOIL)
Four products, and why FOIL is only a special case.
4:06
Algebra 1
Core
Practice ready
Special Products
Three patterns that save time and are essential for factoring later.
34:45
11:22
Algebra 1
Advanced
Practice ready
Factoring Trinomials
Finding two numbers that multiply and add correctly.
11:03
Algebra 1
Advanced
Practice ready
Factoring Special Cases
Difference of squares and perfect square trinomials, spotted instantly.
7:58
Algebra 1
Core
Practice ready
Graphing Parabolas
Vertex, axis of symmetry, direction, and how wide it opens.
7:16
Algebra 1
Core
Practice ready
Solving Quadratics by Factoring
The zero product property, and why one side must be zero first.
11:03
14:05
Algebra 1
Advanced
Practice ready
Completing the Square
Manufacturing a perfect square, and where the quadratic formula comes from.
10:14
Algebra 1
Advanced
Practice ready
The Quadratic Formula
The method that always works, and what the discriminant predicts.
5:58
Algebra 1
Advanced
Quadratic Applications
Projectiles, areas and maximum profit — where parabolas describe reality.
5:31
Algebra 1
Core
Practice ready
Exponential Functions
When the variable moves into the exponent, everything changes.
7:21
Algebra 1
Advanced
Practice ready
Exponential Growth & Decay
Percent change per period, written as a multiplier.
6:16
Algebra 1
Core
Practice ready
Arithmetic Sequences
Adding the same amount each time — a linear function on the integers.
10:45
Algebra 1
Core
Practice ready
Geometric Sequences
Multiplying by the same amount each time — an exponential on the integers.
14:26
Geometry
Intro
Points, Lines & Planes
The three things geometry refuses to define, and why that is deliberate.
15:14
Geometry
Intro
Segment Addition & Midpoints
Adding lengths along a line, and finding the exact middle.
14:24
Geometry
Intro
Angle Relationships
Vertical, linear, complementary and supplementary pairs, used as equations.
7:07
Geometry
Core
Parallel Lines & Transversals
Eight angles, two sizes, and the converses that prove lines parallel.
11:54
Geometry
Core
Conditional Statements & Logic
If-then statements, their converse, inverse and contrapositive.
11:40
Geometry
Advanced
Writing Two-Column Proofs
Statements on the left, reasons on the right, and how to get unstuck.
12:40
3:56
Geometry
Core
What Congruence Means
Same shape and size, defined by motion rather than by measurement.
29:22
15:24
Geometry
Core
Proving Congruence: ASA, AAS & HL
The angle-based criteria, and the one reserved for right triangles.
3:53
9:03
Geometry
Core
Isosceles & Equilateral Triangles
Equal sides force equal angles, and the converse holds too.
5:52
Geometry
Core
Triangle Inequalities
Which three lengths can actually form a triangle, and which angle is biggest.
17:56
Geometry
Advanced
Medians, Altitudes & Centres
Four segments, four points of concurrency, and what each one does.
3:07
Geometry
Core
The Midsegment Theorem
Join two midpoints and you get a parallel segment, half as long.
4:54
Geometry
Core
Similar Polygons
Equal angles, proportional sides, and what scaling does to perimeter and area.
29:22
Geometry
Core
Triangle Similarity: AA, SSS & SAS
Why two angles are enough to prove triangles similar.
23:53
Geometry
Advanced
The Side-Splitter Theorem
A line parallel to one side cuts the other two proportionally.
24:50
Geometry
Advanced
Geometric Mean in Right Triangles
Drop an altitude to the hypotenuse and three similar triangles appear.
2:48
Geometry
Core
Practice ready
The Converse & Pythagorean Triples
Using a² + b² = c² backwards to classify any triangle.
11:11
Geometry
Core
Practice ready
Special Right Triangles
45-45-90 and 30-60-90, and the shortcuts they give you.
10:33
9:10
Geometry
Intro
Polygon Angle Sums
Interior angles grow with the number of sides; exterior angles never do.
20:51
11:02
Geometry
Core
Rectangles, Rhombuses & Squares
Three special parallelograms and the diagonal test for each.
13:36
11:08
Geometry
Advanced
Practice ready
Proving Quadrilateral Types
Choosing the least work needed to classify a shape.
32:30
Geometry
Intro
Circle Vocabulary
Radius, chord, secant, tangent, and the words the theorems depend on.
32:30
14:16
32:30
Geometry
Advanced
Angles from Tangents & Secants
Vertex inside gives half the sum; vertex outside gives half the difference.
32:30
Geometry
Advanced
Chords, Arcs & Segment Lengths
Perpendicular bisectors through the centre, and the products that stay equal.
15:57
3:51
23:34
13:55
3:17
5:29
Geometry
Advanced
Cross-Sections & Solids of Revolution
Slicing a solid, and spinning a flat shape into one.
5:22
9:39
Geometry
Intro
Practice ready
Distance & Midpoint Formulas
The Pythagorean theorem and an average, doing most of coordinate geometry.
9:06
Geometry
Advanced
Coordinate Proofs
Proving a theorem for every case by using variables instead of numbers.
7:22
Geometry
Core
Rigid Motions & Symmetry
Translations, reflections, rotations, and the symmetry they reveal.
4:59
Geometry
Core
Dilations & Similarity Transformations
The one transformation that changes size, and what it preserves.
14:23
5:37
Algebra 2
Advanced
Transformations of Functions
Shifts, stretches and reflections — and why horizontal ones feel backwards.
11:58
Algebra 2
Advanced
Practice ready
Piecewise Functions
Different rules on different intervals, and where the dots go.
6:14
Algebra 2
Advanced
Composition of Functions
Feeding one function's output into another, and why order matters.
14:40
5:19
10:15
Algebra 2
Advanced
Practice ready
Quadratics with Complex Roots
What a negative discriminant means, and why the roots come in pairs.
6:14
Algebra 2
Core
Practice ready
Vertex Form
y = a(x − h)² + k, where the vertex is simply handed to you.
2:07
8:10
5:21
Algebra 2
Advanced
Polynomial Long & Synthetic Division
Dividing polynomials, and the shortcut when the divisor is linear.
6:42
Algebra 2
Advanced
Remainder & Factor Theorems
Testing whether something is a factor without dividing all the way.
12:18
Algebra 2
Advanced
Rational Root Theorem
A finite list of candidate roots to test, instead of guessing.
11:12
7:27
Algebra 2
Core
Simplifying Rational Expressions
Factor first, cancel factors only, and record what x cannot be.
13:14
Algebra 2
Advanced
Multiplying, Dividing, Adding & Subtracting
The fraction rules again, with polynomials in the slots.
3:03
Algebra 2
Advanced
Practice ready
Solving Rational Equations
Clear the denominators, then check for solutions that break the original.
30:16
Algebra 2
Advanced
Graphing Rational Functions
Vertical, horizontal and slant asymptotes, plus holes.
5:30
11:52
Algebra 2
Core
Practice ready
nth Roots & Rational Exponents
Why x^(1/2) means √x, and how that unifies two notations.
10:55
Algebra 2
Core
Practice ready
Operations with Radicals
Adding like radicals, multiplying freely, and clearing denominators.
11:09
Algebra 2
Advanced
Solving Radical Equations
Isolate, square, solve — then check, because squaring lies.
9:15
Algebra 2
Core
Introduction to Logarithms
A logarithm is an exponent. That single sentence is most of the topic.
7:05
Algebra 2
Advanced
Properties of Logarithms
Turning multiplication into addition, and powers into coefficients.
4:13
Algebra 2
Advanced
Solving Exponential & Log Equations
Taking logs to reach an exponent, and exponentiating to escape a log.
22:06
4:26
Algebra 2
Core
Practice ready
Series & Sigma Notation
Reading Σ, and the formulas for arithmetic and geometric sums.
4:45
Algebra 2
Advanced
Practice ready
Infinite Geometric Series
When adding forever still gives a finite answer.
30:10
10:59
Algebra 2
Core
Right Triangle Trigonometry
SOH-CAH-TOA, and finding sides or angles from one another.
10:50
Algebra 2
Advanced
The Unit Circle & Radians
Extending trig past 90°, and the other way to measure an angle.
18:34
4:20
Algebra 2
Core
Circles & Parabolas as Conics
Centre-radius form, and completing the square to find it.
6:37
Algebra 2
Advanced
Matrices & Their Operations
Grids of numbers, and the surprisingly strict multiplication rule.
17:40
Algebra 2
Advanced
Permutations & Combinations
One question decides which formula you need: does order matter?
26:24
Algebra 2
Advanced
Conditional Probability & Distributions
Updating a probability on new information, and the shape of the normal curve.
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