Past Contests

Ongoing and upcoming contests

  • Contest 30

    February 2017 monthly contest.

    Type
    Monthly Contest (Rules)
    Contest window
    Thu, Feb 16 4:55 PM PST to Thu, Feb 16 5:45 PM PST
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO030.pdf
    Problem answers
    Show
    More details
    Show
  • Contest 29

    November 2016 monthly contest.

    Type
    Monthly Contest (Rules)
    Contest window
    Wed, Nov 30 4:55 PM PST to Wed, Nov 30 5:45 PM PST
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO029.pdf
    Problem answers
    Show
    More details
    Show
  • Fall Online Math Open

    Fall OMO 2016. You get an extra hour due to daylight savings time :)

    Type
    Omo Contest (Rules)
    Contest window
    Fri, Nov 4 4:00 PM PDT to Tue, Nov 15 4:00 PM PST
    Teams
    View Team
    Duration
    265 hours and 0 seconds
    Number of problems
    30
    Problems file
    OMOFall16Probs.pdf
    Problem answers
    Show
  • Contest 28

    October 2016 monthly contest.

    Type
    Monthly Contest (Rules)
    Contest window
    Tue, Oct 18 4:55 PM PDT to Tue, Oct 18 5:45 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO028.pdf
    Problem answers
    Show
    More details
    Show
  • Contest 27

    September 2016 monthly contest.

    Type
    Monthly Contest (Rules)
    Contest window
    Mon, Sep 26 4:55 PM PDT to Mon, Sep 26 5:45 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO027.pdf
    Problem answers
    Show
    More details
    Show
  • NIMO Summer Contest 2016

    Summer Contest rules; 15 problems in 15 minutes.

    Type
    Summer Contest (Rules)
    Contest window
    Sat, Aug 6 4:58 PM PDT to Sat, Aug 6 5:17 PM PDT
    Duration
    15 minutes and 0 seconds
    Number of problems
    15
    Problem weights
    1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0 (Total: 120.0)
    Problems and answers
    Problems and answers
    Penalty per minute spent on correct problems
    1.0
  • Contest 26

    May contest; 5 problems in 40 minutes.

    Type
    Monthly Contest (Rules)
    Contest window
    Thu, May 12 4:55 PM PDT to Thu, May 12 5:45 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    5
    Problem weights
    5.0, 7.0, 8.0, 10.0, 12.0 (Total: 42.0)
    Problems file
    NIMO026.pdf
    Problem answers
    Show
    More details
    Show
  • Revenge 25

    NIMO Contest 25, with student submissions

    Type
    Monthly Contest (Rules)
    Contest window
    Tue, Apr 5 4:55 PM PDT to Tue, Apr 5 5:45 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO025.pdf
    Problem answers
    Show
    More details
    Show
  • April 2016 Fun Round

    An April Fool's round for 2016.

    Type
    Monthly Contest (Rules)
    Contest window
    Fri, Apr 1 12:00 AM PDT to Fri, Apr 1 11:59 PM PDT
    Duration
    24 hours and 0 seconds
    Number of problems
    8
    Problem weights
    31.0, 41.0, 26.0, 59.0, 53.0, 58.0, 97.0, 93.0 (Total: 458.0)
    Problems file
    Rhapsody.pdf
    Problem answers
    Show
    More details
    Show
  • Spring 2016 Online Math Open

    OMO Spring 2016, 30 problems as usual.

    Type
    Omo Contest (Rules)
    Contest window
    Fri, Mar 18 4:00 PM PDT to Tue, Mar 29 4:00 PM PDT
    Teams
    View Team
    Duration
    264 hours and 0 seconds
    Number of problems
    30
    Problems file
    OMOSpring16Probs.pdf
    Problem answers
    Show
  • Contest #24

    February contest

    Type
    Monthly Contest (Rules)
    Contest window
    Mon, Feb 22 4:55 PM PST to Mon, Feb 22 5:45 PM PST
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO024.pdf
    Problem answers
    Show
    More details
    Show
  • Contest #23

    January contest

    Type
    Monthly Contest (Rules)
    Contest window
    Thu, Jan 7 4:55 PM PST to Thu, Jan 7 5:45 PM PST
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO023.pdf
    Problem answers
    Show
    More details
    Show
  • Revenge 22

    NIMO Contest 22, with student submissions

    Type
    Monthly Contest (Rules)
    Contest window
    Tue, Dec 8 4:55 PM PST to Tue, Dec 8 5:45 PM PST
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO022.pdf
    Problem answers
    Show
    More details
    Show
  • Fall OMO 2015

    Online Math Open team contest for November 2015. Teams consist of up to four students. NOTE: the start and end time were originally set in the incorrect time zone. Please take note that the start/end time for this contest is 7 PM *Eastern Time*.

    Type
    Omo Contest (Rules)
    Contest window
    Fri, Nov 6 4:00 PM PST to Tue, Nov 17 4:00 PM PST
    Teams
    View Team
    Duration
    264 hours and 0 seconds
    Number of problems
    30
    Problems file
    OMOFall15Probs.pdf
    Problem answers
    Show
  • Contest #21

    NIMO Contest for October 2015.

    Type
    Monthly Contest (Rules)
    Contest window
    Fri, Oct 16 4:55 PM PDT to Fri, Oct 16 5:40 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO021.pdf
    Problem answers
    Show
    More details
    Show
  • Contest #20

    NIMO contest for September 2015.

    Type
    Monthly Contest (Rules)
    Contest window
    Wed, Sep 23 4:55 PM PDT to Wed, Sep 23 5:45 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO020.pdf
    Problem answers
    Show
    More details
    Show
  • Summer Contest 2015

    You may start up to two minutes early and up to two minutes late, but regardless of the start time your contest ends when 15 minutes expires or 5:17 occurs, whichever is sooner.

    Type
    Summer Contest (Rules)
    Contest window
    Sat, Aug 8 4:58 PM PDT to Sat, Aug 8 5:17 PM PDT
    Duration
    15 minutes and 0 seconds
    Number of problems
    15
    Problem weights
    1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0 (Total: 120.0)
    Problems and answers
    Problems and answers
    Penalty per minute spent on correct problems
    1.0
  • Contest 19

    May Contest.

    Type
    Monthly Contest (Rules)
    Contest window
    Tue, May 19 4:55 PM PDT to Tue, May 19 5:45 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    5
    Problem weights
    5.0, 7.0, 8.0, 10.0, 12.0 (Total: 42.0)
    Problems file
    NIMO019.pdf
    Problem answers
    Show
    More details
    Show
  • Spring OMO 2015

    The Spring installment of the 2014-2015 OMO contests. NOTE: In #29 the side length of BC should be 20x^(5/2), not 10x^(5/2). The original formulation of the problem leads to a unique value of x, but for which the resulting triangle ABC does not fit the problem criteria. The new formulation fixes this issue. We will grade as correct the answer obtained under either formulation, i.e., if your team solved the original version of the #29 there is no need to redo the problem as the answer originally submitted will still be graded correct.

    Type
    Omo Contest (Rules)
    Contest window
    Fri, Apr 3 4:00 PM PDT to Tue, Apr 14 4:00 PM PDT
    Teams
    View Team
    Duration
    264 hours and 0 seconds
    Number of problems
    30
    Problems file
    OMOSpring15Probs.pdf
    Problem answers
    Show
  • April 2015 Fun Round

    An April Fool's event for 2015. NOTE: There was an error in the indices i and j for Problem 4 which has now been fixed. We apologize for the mistake.

    Type
    Monthly Contest (Rules)
    Contest window
    Wed, Apr 1 12:00 AM PDT to Wed, Apr 1 11:59 PM PDT
    Duration
    24 hours and 0 seconds
    Number of problems
    8
    Problem weights
    2.0, 1.0, 3.0, 4.0, 7.0, 11.0, 18.0, 29.0 (Total: 75.0)
    Problems file
    Tribute.pdf
    Problem answers
    Show
    More details
    Show
  • Contest 18

    March Contest

    Type
    Monthly Contest (Rules)
    Contest window
    Sun, Mar 22 4:55 PM PDT to Sun, Mar 22 5:45 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO018.pdf
    Problem answers
    Show
    More details
    Show
  • Revenge 17

    January Revenge Contest

    Type
    Monthly Contest (Rules)
    Contest window
    Fri, Jan 23 4:55 PM PST to Fri, Jan 23 5:45 PM PST
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO017.pdf
    Problem answers
    Show
    More details
    Show
  • Contest 16

    November Contest 2014

    Type
    Monthly Contest (Rules)
    Contest window
    Wed, Nov 19 4:55 PM PST to Wed, Nov 19 5:45 PM PST
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO016.pdf
    Problem answers
    Show
    More details
    Show
  • OMO Fall 2014

    Fall 2014 contest. As usual, teams of four submit answers to 30 problems over the span of about a week.

    Type
    OMO Contest (Rules)
    Contest window
    Fri, Oct 17 4:00 PM PDT to Tue, Oct 28 4:00 PM PDT
    Teams
    View Team
    Duration
    264 hours and 0 seconds
    Number of problems
    30
    Problems file
    OMOFall14Probs.pdf
    Problem answers
    Show
  • Contest 15

    September Contest 2014

    Type
    Monthly Contest (Rules)
    Contest window
    Mon, Sep 15 4:55 PM PDT to Mon, Sep 15 5:45 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO015.pdf
    Problem answers
    Show
    More details
    Show
  • Summer Contest 2014

    The NIMO 2014 Summer Contest. As usual, 15 problems in 15 minutes, where problem N is worth N points.

    Type
    Summer Contest (Rules)
    Contest window
    Sat, Aug 23 4:57 PM PDT to Sat, Aug 23 5:17 PM PDT
    Duration
    15 minutes and 0 seconds
    Number of problems
    15
    Problem weights
    1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0 (Total: 120.0)
    Problems and answers
    Problems and answers
    Penalty per minute spent on correct problems
    1.0
  • Contest 14

    May 2014 Contest.

    Type
    Monthly Contest (Rules)
    Contest window
    Fri, May 16 4:55 PM PDT to Fri, May 16 5:45 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO014.pdf
    Problem answers
    Show
    More details
    Show
  • OMO Spring 2014

    The OMO contest for Spring 2014. 30 problems from April 4 to April 15 at 4PM PT / 7PM ET each day.

    Type
    OMO Contest (Rules)
    Contest window
    Fri, Apr 4 4:00 PM PDT to Tue, Apr 15 4:00 PM PDT
    Teams
    View Team
    Duration
    264 hours and 0 seconds
    Number of problems
    30
    Problems file
    OMOSpring14Probs.pdf
    Problem answers
    Show
  • April Fools' 2014

    Have fun! :)

    Type
    Monthly Contest (Rules)
    Contest window
    Mon, Mar 31 6:00 PM PDT to Tue, Apr 1 11:59 PM PDT
    Duration
    30 hours and 0 seconds
    Number of problems
    9
    Problem weights
    2.0, 3.0, 5.0, 7.0, 11.0, 13.0, 17.0, 19.0, 23.0 (Total: 100.0)
    Problems file
    Tragedy9.pdf
    Problem answers
    Show
    More details
    Show
  • Revenge 13

    Due to server downtime, we are not able to access the student-submitted proposals for the February contest. We will just defer the student-written contest to the March monthly contest.

    Type
    Monthly Contest (Rules)
    Contest window
    Mon, Mar 24 4:55 PM PDT to Mon, Mar 24 5:45 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO013.pdf
    Problem answers
    Show
    More details
    Show
  • Contest 12

    Due to server downtime, we are not able to access the student-submitted proposals for the February contest. We will just defer the student-written contest to the March monthly contest.

    Type
    Monthly Contest (Rules)
    Contest window
    Mon, Feb 24 4:55 PM PST to Mon, Feb 24 5:45 PM PST
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO012.pdf
    Problem answers
    Show
    More details
    Show
  • Contest 11

    January 2014 contest.

    Type
    Monthly Contest (Rules)
    Contest window
    Fri, Jan 31 4:55 PM PST to Fri, Jan 31 5:45 PM PST
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO011.pdf
    Problem answers
    Show
    More details
    Show
  • 2014 NIMO Winter Contest

    The 2014 Winter Contest is, like its a predecessors, a proof-based contest for teams of up to four. Teams may communicate online, and type their solutions. The contest has a time limit of one hour. The remaining 30 minutes of the time period are to be used only for compiling and uploading solutions.

    Type
    Winter Contest (Rules)
    Contest window
    Wed, Jan 1 12:00 AM PST to Mon, Jan 13 11:59 PM PST
    Teams
    View Team
    Duration
    1 hour, 30 minutes and 0 seconds
    Number of problems
    8
    Problems file
    Problems.pdf
    Scores
    Scores are available! View your score here.
  • Contest 10

    December 2013 contest.

    Type
    Monthly Contest (Rules)
    Contest window
    Tue, Dec 3 4:55 PM PST to Tue, Dec 3 5:45 PM PST
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO010.pdf
    Problem answers
    Show
    More details
    Show
  • Revenge 9

    The student-written contest. There will be eight questions to solve over 40 minutes. To participate, click the "Start/Continue Contest" link at the start of the contest window.

    Type
    Monthly Contest (Rules)
    Contest window
    Wed, Nov 13 4:55 PM PST to Wed, Nov 13 5:45 PM PST
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO9.pdf
    Problem answers
    Show
    More details
    Show
  • OMO Fall 2013

    OMO contest for Fall 2013.

    Type
    OMO Contest (Rules)
    Contest window
    Fri, Oct 18 4:00 PM PDT to Tue, Oct 29 4:00 PM PDT
    Teams
    View Team
    Duration
    264 hours and 0 seconds
    Number of problems
    30
    Problems file
    OMOFall13Probs.pdf
    Problem answers
    Show
  • Contest 8

    NIMO Monthly Contest for September 2013.

    Type
    Monthly Contest (Rules)
    Contest window
    Tue, Sep 24 4:55 PM PDT to Tue, Sep 24 5:50 PM PDT
    Duration
    40 minutes and 0 seconds
    Number of problems
    8
    Problem weights
    5.0, 5.0, 6.0, 6.0, 7.0, 8.0, 9.0, 10.0 (Total: 56.0)
    Problems file
    NIMO8.pdf
    Problem answers
    Show
    More details
    Show
  • Summer Contest 2013

    The NIMO 2013 Summer Contest. 15 problems, 15 minutes. Problem n is worth n points. Tiebreaking is done by highest problem solved. In the event that there is still a tie, a penalty equal to the sum of the number of minutes spent on each correctly answered problem will be used to break the tie.

    Type
    Summer Contest (Rules)
    Contest window
    Sat, Aug 10 5:00 PM PDT to Sat, Aug 10 5:25 PM PDT
    Duration
    15 minutes and 0 seconds
    Number of problems
    15
    Problem weights
    1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0 (Total: 120.0)
    Problems and answers
    Problems and answers
    Penalty per minute spent on correct problems
    1.0