OSN Coaching Mathematics SMA

Algebra: Inequalities (HM-GM-AM-QM, Cauchy-Schwarz, Jensen, etc.); Basic identities & algebraic substitution; Sequences: patterns, induction, linear recurrences (Fibonacci, Lucas), periodicity; Polynomial properties & equations; Classic functional equations (Cauchy, Jensen, d'Alembert); Function properties: injective/surjective/bijective, monotone, bounded, convex/concave. Geometry: Angle chasing & cyclic quadrilaterals; Triangles: medians, perpendicular bisectors & circumcircle, altitudes, angle bisectors & incircle/excircles, isogonal conjugates; Circles: power of a point, radical axis & centre, Ptolemy, Simson line. Combinatorics: Sum & product rules, permutations, combinations, distributions, partitions; Binomial & multinomial coefficients, Pascal's triangle, Chu Shih-Chieh identity; Probability: disjoint/independent events, conditional probability, Bayes' rule; Set theory & De Morgan's laws. Number Theory: Divisibility, GCD, LCM, primes, simple Diophantine equations; Modular congruences; Wilson, Fermat, and Euler theorems; Order & primitive roots; Congruence equations, Chinese remainder theorem, quadratic residues

OSN-S (School) (January – February 2026): Selection at each school; schools register up to 5 students per field.. OSN-K (District/City) (18–19 June 2026): 10 multiple choice + 10 short answer, 2 hours 30 minutes. OSN-P (Province) (27–29 July 2026): 8 short answer + 4 essays, 4 hours. National Semifinal (12 August 2026): 5 essay questions, 4 hours. National Final (14–20 September 2026 (in person)): Day 1: 4 essays · Day 2: 4 essays, 4 hours per day.

Senior High students who want to take part in the OSN Mathematics field, whether beginners or returning participants.

Yes. OSN Mathematics SMA training at Presisi Academy runs online with live classes, graded practice, and selection simulations. In-person classes are coming soon.