Simple Interest calculations with practical examples. Problem-solving steps: (1) identify P, R, T, (2) apply formula I = PRT/100, (3) calculate amount A = P + I. Example: P=10000, R=5%, T=2 years gives I = 10000×5×2/100 = 1000, A = 11000. Common traps: misidentifying principal, confusing rate basis (annual vs monthly). Exam tips: state all unknowns clearly, verify reasonableness. Time-saving: estimate before exact calculation. Variations: finding P, R, T when others known requires formula rearrangement. Multi-year calculations: treat year-by-year to verify. Applications: loan interest, bank deposits, comparative financial decisions. Verification method: recalculate with different formula arrangement. Understanding calculations essential for financial literacy. Practice increasingly complex scenarios.