When number pyramids have a sequence on the bottom layer, some interesting patterns emerge...
Three people chose this as a favourite problem. It is the sort of
problem that needs thinking time - but once the connection is made
it gives access to many similar ideas.
Libby Jared helped to set up NRICH and this is one of her favourite
problems. It's a problem suitable for a wide age range and best
You have 27 small cubes, 3 each of nine colours. Use the small cubes to make a 3 by 3 by 3 cube so that each face of the bigger cube contains one of every colour.
Lyndon chose this as one of his favourite problems. It is
accessible but needs some careful analysis of what is included and
what is not. A systematic approach is really helpful.
There are many different methods to solve this geometrical problem - how many can you find?
A new problem posed by Lyndon Baker who has devised many NRICH
problems over the years.
Nick Lord says "This problem encapsulates for me the best features
of the NRICH collection."
Go to last month's problems to see more solutions.
Professor Korner has generously supported school mathematics for more than 30 years and has been a good friend to NRICH since it started.
Can you beat the computer in the challenging strategy game?
A Sudoku with clues as ratios.