The math you are already using.
A cooling coffee, a loan statement, the slope of a curve: each one runs on a formula you can write down and check. These pages show the formula, the steps and where it came from.
Slide the dot along the coffee's curve
Steep: the coffee is cooling fast.
Pick a corner of everyday math
Math in daily life
Where calculus and everyday arithmetic turn up in a normal day: rates of change, totals, sleep, unit prices and the best choice among options.
5 pages →Core ideas
Limits, derivatives, integrals, the chain rule, optimization and the Fundamental Theorem of Calculus, each with worked examples.
7 pages →Math of money
Loan payments, payoff time, compound interest, APR vs APY, the Rule of 72, tax brackets, rent vs buy and retirement targets, with calculators and worked examples.
8 pages →Math of health
The equations behind resting metabolic rate, total daily energy expenditure and maximum heart rate, with their sources and their limits.
4 pages →Math in the world
Cooling coffee, why the seasons happen, pi and why power lines run at high voltage: familiar things with a calculation inside.
5 pages →Learning math
How to study calculus, a topic roadmap, free courses and textbooks, and how to talk about math with children.
1 page →Why you can check our work
Looking at a loan?
The payment formula, step by step, with a worked example and a calculator you can redo.