INMO 2025: Indian National Mathematical Olympiad (by HBCSE)

What is INMO?

The Indian National Mathematical Olympiad (INMO) is the third stage in India’s mathematics Olympiad program. Organized by Homi Bhabha Centre for Science Education (HBCSE) under NBHM, it follows the Regional Mathematical Olympiad (RMO) and identifies top talent for the International Mathematical Olympiad (IMO) selection.

Eligibility & Selection Process

1. Stage 1 – IOQM (formerly PRMO): Qualifier with ~30 integer-response questions; ~900 students advance.
2. Stage 2 – RMO: 3-hour paper with 6 challenging problems; top performers (~300–450) get selected.
3. Stage 3 – INMO: About 900 students (30 from classes 8–11, 6 from class 12 per region + five girls' quota) qualify for INMO.
4. Stage 4 – IMOTC & PDC: Top ~35 from INMO attend training camp; 6 finalists chosen for the IMO team.

INMO 2025 Exam Pattern

• Date: 3rd Sunday of January.
• Duration: 4 hours 30 minutes.
• Format: 6 subjective problems, equally weighted, requiring full solutions .
• Total Marks: ~102 (typically 17 points each) without negative marking.
• Allowed Materials: Non-programmable scientific calculator, geometry tools (ruler, compass).

Syllabus & Topics

Based on pre-degree CBSE class XI–XII math but includes challenging Olympiad problems:

• Algebra: Polynomials, equations, inequalities, sequences & series, complex numbers, functional equations.
• Geometry: Euclidean geometry, circle theorems, advanced constructions.
• Number Theory: Integer arithmetic, divisibility, modular/congruences, elementary combinatorics.
• Combinatorics & Probability: Counting, graph theory, basic probabilities.
• Calculus-Like Tools: Optional methods may be used, but problems avoid heavy calculus .

Preparation Cheat Sheet

• Past Papers: Practice INMO & RMO past papers with full solutions.

• Essential Texts:

  • Challenge & Thrill of Pre‑College Mathematics – for combinatorics, algebra.
  • Euclidean Geometry in Mathematical Olympiads or Loney’s geometry texts.
  • Functional Equations and Inequalities by Venkatachala.

• Strategy:

  • Develop proof-writing: clarity, presentation, rigor.
  • Work with peers/mentors; discuss alternate solutions.
  • Focus on conceptual depth over speed at this level.

Awards & Recognition

• Top ~35 students qualify for the IMO Training Camp (IMOTC).
• Certification as INMO awardees, with access to NBHM scholarships (~₹2,500/month).
• Direct entry benefits for premier institutes like CMI B.Sc.(Hons) and ISI B.Stat/B.Math.

Quick Overview