Compound Interest calculations with examples. Problem steps: (1) identify P, r, n (time periods), compounding frequency, (2) calculate (1 + r/100), (3) raise to power n, (4) compute A and CI. Example: P=10000, r=5%, annually, 2 years: A = 10000(1.05)^2 = 10000×1.1025 = 11025, CI = 1025. Common traps: wrong power, incorrect frequency adjustment, rounding errors. Exam tips: be precise with powers, verify intermediate calculations. Time-saving: pre-calculate (1 + r/100) value, reuse for multiple periods. When r varies: calculate year-by-year with new r. Calculator usage: master power function, use log for large powers. Verification: result > P, reasonable growth rate. Applications: savings goals, investment returns, loan amortization. Practice with consistent frequency before mixing.