Finance basics include simple interest, compound interest, present/future value, and annuities. Simple interest I = (P × R × T) / 100, where P = principal, R = rate (%), T = time (years). Amount A = P + I = P(1 + RT/100). Compound interest A = P(1 + r/100)^n, where r = rate, n = periods. Effective rate accounts for compounding frequency. Example: P = 10,000, R = 10% p.a., T = 2 years. SI = 2,000, A = 12,000. CI: A = 10,000(1.1)² = 12,100. Difference = 100. Shortcut: For quick comparison, CI is always ≥ SI. Exam tip: Identify whether problem specifies simple or compound. Read carefully for frequency (annual, quarterly, monthly).