SOF IMO study guide
SOF IMO · Work through your exam, one topic at a time.
The SOF International Mathematics Olympiad (IMO) is an annual school-based mathematics competition run by the Science Olympiad Foundation (SOF) for students in classes 1 to 12. It is aimed at students enrolled in a school recognised by SOF, and it is designed to assess mathematical reasoning and logical ability rather than rote recall. The exam is held once a year, is delivered offline in English, and runs for 1 hour; the registration fee is ₹170. Participation is arranged through school authorities - students cannot apply individually, and schools are asked to submit the form at least 30 days before the exam date. Level 1 is open to classes 1–12, with three scheduled dates in the 2026-27 cycle: 23 October 2026, 26 November 2026 and 10 December 2026. There is a second level for classes 3–12 only; classes 1 and 2 finish at Level 1. Topics on this exam: Mathematical reasoning and logical ability. The SOF IMO study guide has 1 section and about 391 words.
01Mathematical Reasoning and Logical Ability - SOF IMO
Mathematical Reasoning and Logical Ability is the backbone of the SOF IMO paper: it checks whether you can spot structure in numbers, codes, patterns and arrangements rather than recall formulas. It supplies most of the Logical Reasoning and Mathematical Reasoning questions, and the hardest variants reappear in the Achievers section. Expect series and analogies, odd-one-out, coding–decoding, direction and ranking puzzles, blood relations, clocks and calendars, Venn diagrams, figure patterns, plus arithmetic and geometry reasoning. Number series: test first differences, then second differences, then ratios; if nothing fits, split into two interleaved series and check squares or cubes plus or minus a constant.
391 words, about 2 minMore study resources for SOF IMO
- Practice questionsA number is described as 'the smallest positive integer that leaves a remainder of 2 when divided by 3, a remainder of 3 when divided by 5, and a remainder of 2 when divided by 7.' What is this number?
- FlashcardsDivisibility by 9. A number is divisible by 9 exactly when the sum of its digits is divisible by 9; repeatedly summing digits gives the digital root, which equals the remainder modulo 9.
- Cheat sheetDivisibility rules: 3 and 9 use digit sums; 4 uses the last two digits; 8 uses the last three digits; 11 uses alternating digit sums; 6 requires divisibility by both 2 and 3.
- Key termsdivisibility. The property that one whole number can be divided by another with no remainder.
- Study planDiagnose current strengths by solving 25 mixed IMO-style problems under timed conditions and logging error types (algebra, combinatorics, geometry, number theory, logic).
- Common mistakesUnder time pressure the brain pattern-matches to a familiar problem type and skips the qualifier ('not', 'at least', 'in terms of', 'how many more').
- Exam-day guidePrint or download the admission document issued for your registration.