FOBISIA Code Breaking Maths Challenge

You will find the 2025 FOBISIA competition in the menu above.  This will run from Monday 22nd September 2025 until Friday 26th September 2025.  

Code Levels 1A and 1B are intended to be accessible to both KS2 and KS3 students

Code Levels 2A and 2B are intended more for KS3 and KS4 students

Code Levels 3 is intended for KS4 and KS5 students.

Code Level 4 is intended for KS5 students and teachers.

Bonus Code Level is an added challenge in which students learn how to use Python programming to crack codes.

If you are a teacher then please also check out my intermathematics resources for supporting IB Mathematics.  At the last count, several thousand pages of worksheets, puzzles, quizzes, tests and more.

Maths and code breaking have a long and shared history. The skills that make good mathematicians, problem solving, logical thought and perseverance are the same skills that make great code breakers.

Governments and companies that deal in digital data are always on the look out for talented mathematicians – so who knows, maybe one day you could be a professional code maker or code breaker.

Many thanks – and good luck!

Andrew Chambers