Budget Planner : Correctly sums expenses and computes remaining income.

Growing Annuity : Handles rate equality and uses the correct formula.

Beta Estimator : Applies CAPM logic for beta calculation.

Markup/Margin : Computes both metrics with valid input checks.

Interest-Only Loan : Calculates monthly interest correctly.

Rule of 100 : Provides age-based allocation.

Drawdown : Measures percentage decline from peak.

CAGR : Uses the standard formula.

Gold Inflation : Compares price changes.