Doing math is life-changing.✱
A quick warm-up: four easy problems. No sign-up. Start with the one here.
Warm-up, problem 1 of 4
warm-up · 1 of 4
3 + 2
- problem 1: now
- problem 2: to come
- problem 3: to come
- problem 4: to come
What you get
- Beat par, earn ✱. Every problem has a target time. Right and inside it earns ✱; inside half of it, two.
- XP levels you up. Every right answer earns XP, even a slow one. Levels open new courses.
- A shop for your ✱. Themes, name flair and titles. Looks only: nothing you buy changes your pay.
- A daily box and a streak. Ten cards a day, easy to hard. Every 14 days in a row pays a bonus.
- Friends and a leaderboard. Follow friends, see who practiced today, and climb the weekly board.
What you can learn
Foundations
Mental Arithmetic
- 1 Small facts
- 2 Gaps & place value
- 3 Times tables
- 4 Two-digit add & subtract
- 6 Division
- 10 Bigger multiplication
- 11 Grouping & estimating
- 14 Everyday mix
Fractions, Decimals & Percents
- 5 Fraction basics
- 7 Decimals
- 8 Percents
- 12 Fraction arithmetic
- 13 What percent? Work backward
- 13 Money & prices
Business
Business Math
- 1 First Business Story
- 2 Percentages in Business
- 4 Markup Is Not Margin
- 8 Solve for the Unknown
- 13 Fixed, Variable & Step Costs
- 14 Contribution Margin
- 15 Break-Even
- 18 Pricing Decisions
- 33 Hiring Math
- 40 Operator I: Read Greenline
- 46 Operator II: Make the Call
- 56 Pricing Models (Applied Calculus)
Accounting
- 3 The Accounting Equation
- 5 Cash In Is Not Always Revenue
- 6 Reading a P&L
- 16 Profit Is Not Cash
- 19 Margins on the P&L
- 20 The Balance Sheet
- 22 Debits & Credits
- 35 Depreciation
- 37 The Cash Flow Statement
- 38 Financial Ratios
Bookkeeping
- 7 Sorting Transactions
- 17 Invoices & Sales Tax
- 26 Journal Entries
- 27 Bank Reconciliation
- 29 Payroll Basics
- 31 Receivables & Payables Aging
- 36 Inventory & Cost of Goods Sold
Finance & Money
- 9 Money Basics
- 20 Compound Growth
- 24 Personal Finance
- 32 Present Value
- 34 Loans & Amortization
- 40 NPV & Payback
- 45 CAGR & Doubling
Growth & Marketing Math
- 10 Funnels
- 23 Customer Acquisition Cost
- 25 Churn & Retention
- 34 Payback & Lifetime Value
- 39 Cohorts & Revenue Retention
Business Stats & Decisions
- 12 Averages & Spread
- 21 Probability Basics
- 27 Expected Value
- 28 Cash Forecasts
- 30 Forecasts & Budgets
- 37 Base Rates & Conditional Rates
- 38 Runway & Scenarios
- 39 Data Traps
- 41 A/B Tests
Thinking
Thinking
- 1 Orders of magnitude
- 17 Fermi estimates
- 19 Mental shortcuts
- 20 Growth & projection
- 21 Expected value
- 28 Base rates
- 35 Risk & the long run
- 49 Decision math
School math
Pre-Algebra
- 9 Negative numbers
- 11 Order of operations
- 14 Factors & primes
- 15 Expressions & one-step equations
- 18 Exponents & roots
- 19 Ratios & proportions
Geometry
- 11 Angles
- 17 Area & perimeter
- 22 Circles
- 23 Pythagoras & coordinates
- 26 Solids & scaling
Probability & Statistics
- 12 Averages
- 18 Chance basics
- 22 Spread
- 24 Combined events
- 29 Conditional probability
- 33 Expected value & variance
- 34 The normal curve
- 43 Correlation & regression
Counting & Discrete Math
- 15 Counting
- 25 Combinations
- 32 Logic & sets
- 42 Recurrences
- 47 Graphs & networks
Algebra
- 16 Linear equations
- 21 Lines & slope
- 23 Inequalities
- 24 Systems of equations
- 26 Polynomials
- 27 Functions
- 28 Quadratics
- 29 Sequences & series
- 30 Exponentials & logarithms
Number Theory
- 16 Divisibility
- 25 Number bases
- 31 Clock arithmetic
- 44 Congruences
Trigonometry
- 30 Right-triangle trig
- 32 Radians & the unit circle
- 36 Laws of sines & cosines
- 43 Identities & equations
College & beyond
Calculus
- 31 Limits
- 33 Derivatives
- 36 Using derivatives
- 41 Integrals
- 44 Integration techniques
- 50 Series
- 51 Several variables
Linear Algebra
- 35 Vectors
- 42 Matrices
- 48 Inverses & rank
- 52 Eigenvalues
Beyond College
- 53 Complex numbers
- 54 Numerical methods
- 55 Differential equations
- 57 Real analysis
- 58 Abstract algebra
- 59 Probability theory
- 60 Complex analysis
✱ Someone edited "Doing Math" onto a viral chart of life-changing nootropics as a joke. We thought the joke should be true, so we built this. The story →