Algebra
Equations, factoring, quadratics, systems — the spine of everything above it.
- Equation Solver
- Factoring Calculator
- Quadratic Formula
- Systems of Equations
Step-by-step math, free
Every answer
shows its reasoning.
Most calculators hand you a number and leave. Ours writes out the working and names the rule behind every line — so the next problem is one you solve yourself.
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- x² + 5x + 6 = 0 the equation
- (x + 2)(x + 3) = 0 two numbers multiplying to 6, adding to 5
- x + 2 = 0 or x + 3 = 0 zero product property
- x = −2 or x = −3 solve each factor
Verified by a mathematician
Calculators
Ten branches, one method
grouped the way maths itself is taught, not by popularity
Fractions
Add, simplify, convert, compare.
- Fraction Calculator
- Adding Fractions
- Mixed Numbers
Basic Math
Roots, percentages, factors, long division.
- Square Root
- Percentage
- GCF & LCM
Geometry
Area, volume, slope, the theorems behind them.
- Pythagorean Theorem
- Area
- Slope
Calculus
Limits, derivatives, integrals, series.
- Derivative
- Integral
- Limit
Trigonometry
Angles, ratios, identities, triangle solving.
- Trig Calculator
- Radians to Degrees
- Sin, Cos, Tan
Statistics
Averages, spread, probability, distributions.
- Mean, Median, Mode
- Standard Deviation
- Probability
Graphing
Plot functions, read domain, range and inverses.
- Function Graph
- Domain & Range
- Inverse Function
Pre-Algebra
Integers, ratios, exponent rules, first variables.
- Integers
- Proportions
- Exponent Rules
Converters
Between units, forms and notations.
- Celsius to Fahrenheit
- Decimal to Fraction
- Scientific Notation
Knowledge base
Nobody is standing over your shoulder
so every page answers what a teacher would have
“What do I need to know first?”
Every topic names its prerequisites and links straight to them. Get stuck on quadratics and the page points you back to factoring, then to exponents, as far down as you need to go.
Open the knowledge base“Where did I go wrong?”
Each topic has a page for the mistakes people actually make in it — sign errors, dropped denominators, the step everyone skips. This is the page you cannot get from a calculator that only prints answers.
See a mistakes page“What now?”
Finish a topic and the next one is already chosen for you, with a practice set attached. Follow the chain far enough and you end up somewhere you would not have picked yourself.
Follow a learning pathWhere to start
Start where you actually are
each stage assumes the one before it
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01
Foundations
The arithmetic everything later leans on. If algebra keeps going wrong, the cause is usually one of these four.
- What is a fraction?Fractions
- Fraction rulesFractions
- How to add fractionsFractions
- Simplify a square rootBasic Math
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02
Into algebra
Where letters start standing in for numbers. Nothing new is being asked of the arithmetic — only of the notation.
- Solve a proportionPre-Algebra
- Mixed vs improperFractions
- Factor a trinomialAlgebra
- Slope-intercept formGraphing
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03
Further out
Geometry, angles and rates of change. Each one is algebra applied to a new kind of question.
- Pythagorean theoremGeometry
- Degrees and radiansTrigonometry
- What is a derivative?Calculus
- Mean, median and modeStatistics
Start at the leftmost stage you are not sure about — everything to the right of it depends on it. Browse all explainers
Most used
Where people start
by traffic over the last 30 days
Checked by a mathematician before it goes live
Every calculator and every explainer is reviewed for mathematical accuracy by a qualified maths teacher, and dated so you can see when it was last checked. We do not offer tutoring — we make the material good enough that you do not need it.