National Internet Math Olympiad

The National Internet Math Olympiad (NIMO) was a team-based series of online math tests for high school students. It was organized by Evan Chen.


Online Math Open

The Online Math Open (OMO) was a math Olympiad held in fall and spring. There are 30 questions (each worth 1 point), and each answer is a nonnegative integer less than or equal to $2^{31} - 1 = 2147483647$. The test lasts for 12 days. The only electronic math tool allowed is a four-function calculator.

Region: USA
Type: Short Answer
Difficulty: 1-9.5
Difficulty Breakdown:

Problem 1-5: 1-3
Problem 6-10: 3-4
Problem 11-15: 4.5-5.5
Problem 16-20: 6
Problem 21-25: 7-8
Problem 26-30: 8-9.5

NIMO Summer Contest

The NIMO Summer Contest was another online contest where each question was worth the respective question’s number points. Solvers can not return to a problem when a problem was skipped.

NIMO Monthly Contest

The NIMO Monthly Contest has 8 questions that must be solved in 40 minutes. Solvers can submit up to 3 attempts.

As of 2018, the NIMO Monthly Contest has been discontinued.