Here are some places where you can find free collections of interesting mathematical articles, challenges and puzzles to explore:
- Brilliant is a US website that provides a brilliant selection of challenging mathematical problems.
- Mathigon is a collection of free recreational maths articles, activities and puzzles that aim to make maths more accessible and entertaining.
- MathsChallenge.net offers a collection of maths puzzles with a range of difficulty levels to choose from.
- MEI has produced several free apps and games.
- Mr Barton Maths includes a selection of maths and logic puzzles, and maths jokes too!
- NRICH provides a collection of activities and games.
- Numberphile is a collection of fascinating videos about numbers.