Hidden Treasures

Hidden Treasures

To celebrate NRICH's 20th birthday, we've taken a look back in the archives and dusted off some problems from the early days, freshened them up, and added some new ideas. We hope your students will enjoy working on these hidden treasures!

Calendar Capers 

Age 11 to 14 Challenge Level:
Choose any three by three square of dates on a calendar page...

Counting Factors 

Age 11 to 14 Challenge Level:
Is there an efficient way to work out how many factors a large number has?

Latin Numbers 

Age 14 to 16 Challenge Level:
Can you create a Latin Square from multiples of a six digit number?

Building Tetrahedra 

Age 14 to 16 Challenge Level:
Can you make a tetrahedron whose faces all have the same perimeter?

Gift of Gems 

Age 14 to 16 Challenge Level:
Four jewellers share their stock. Can you work out the relative values of their gems?

Rationals Between... 

Age 14 to 16 Challenge Level:
What fractions can you find between the square roots of 65 and 67?