### Consecutive Numbers

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

### Calendar Capers

Choose any three by three square of dates on a calendar page...

### Building Tetrahedra

Can you make a tetrahedron whose faces all have the same perimeter?

# Producing an Integer

##### Stage: 3 and 4 Short Challenge Level:

When is the value of the product $$\left(1 + {1 \over 2}\right)\left(1 + {1 \over 3}\right)\left(1 + {1 \over 4}\right)...\left(1 + {1 \over n}\right)$$ equal to an integer?

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

This problem is taken from the UKMT Mathematical Challenges.
View the archive of all weekly problems grouped by curriculum topic