Lessons

Clear lessons in arithmetic, algebra, geometry, trigonometry, statistics, probability and calculus with worked examples and practice.

Arithmetic

Order of operations6 minWhy 2 + 3 × 4 is 14 and not 20: the agreed order in which an expression is evaluated.Working with fractions9 minEquivalent fractions, lowest terms, and the four operations — with the reasons behind the rules.

Algebra

Solving linear equations8 minKeep the balance: how to isolate the unknown in any first-degree equation.Quadratic equations11 minFactoring, completing the square and the quadratic formula — and what the discriminant tells you.

Geometry

The Pythagorean theorem8 minThe relationship between the sides of a right triangle, why it is true, and how it measures distance.

Trigonometry

The unit circle and trigonometric functions10 minSine, cosine and tangent as coordinates on a circle; radians; and the identities worth remembering.

Statistics

Mean, median and standard deviation10 minHow to describe the centre and the spread of a data set, and which measure to trust when.

Probability

The basic rules of probability10 minComplement, addition and multiplication rules, conditional probability and independence.

Calculus

Introduction to derivatives12 minThe derivative as a rate of change and the slope of a tangent, and the rules that make it computable.Introduction to integrals12 minArea as a limit of sums, antiderivatives, and the theorem that connects them.

About the Lessons

Each lesson explains one topic from the ground up: the idea, the formulas, worked examples, the mistakes people make most often, and a few problems to try. Lessons link to the tools that carry out the calculations they describe, so you can check your own work.

The collection covers arithmetic, algebra, geometry, trigonometry, statistics, probability and calculus.

How to use it

Pick a lesson from the list.
Read the explanation and work through the examples.
Try the practice problems, then open Practice Mode for unlimited checked problems on the same topic.

Example

Quadratic equations

→ Factoring, completing the square, the quadratic formula and the discriminant

Formula LibraryA searchable library of formulas for algebra, geometry, trigonometry, statistics, probability, calculus and physics, each with an example.Practice ModeRandomised practice problems by topic and difficulty with instant answer checking, hints, explanations and score tracking.Math PlaygroundA multi-line scratchpad: define variables and functions, then build on earlier lines with live results as you type.

Arithmetic

Algebra

Geometry

Trigonometry

Statistics

Probability

Calculus

About the Lessons

How to use it

Related tools

Arithmetic

Algebra

Geometry

Trigonometry

Statistics

Probability

Calculus

About the Lessons

How to use it