Finance & Math guides
4 guides — practical answers with the math shown, each paired with a free calculator.
How Are Loan Payments Calculated? Amortization, Explained
One level payment, front-loaded interest — the formula worked by hand, the two levers you control, and why the smaller payment is often the costlier loan.
July 23, 2026 · 13 min read
How Much Should You Tip? Rates by Situation, With the Math
The customary rates by setting, the three-line formula, and the split order that keeps the tip at the rate you chose.
July 23, 2026 · 12 min read
How to Calculate Take-Home Pay: From Gross to What You Keep
One combined deduction rate, your pay schedule, and a two-minute pay stub calibration — gross to net in two lines of math.
July 23, 2026 · 13 min read
How Does Compound Interest Work? The Math That Grows Money
Interest that earns interest — the formula, the frequency gap, and why steady deposits and time do most of the work.
July 20, 2026 · 7 min read