You may also like

problem icon

Calendar Capers

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

problem icon

Card Trick 2

Can you explain how this card trick works?

problem icon

The Patent Solution

A combination mechanism for a safe comprises thirty-two tumblers numbered from one to thirty-two in such a way that the numbers in each wheel total 132... Could you open the safe?

Pairs

Age 11 to 14 Challenge Level:

Ann thought of 5 numbers and told Bob all the sums that could be made by adding the numbers in pairs. The list of sums is 6, 7, 8, 8, 9, 9, 10,10, 11, 12. Help Bob to find out which numbers Ann was thinking of.

[This is an exercise for practice from the Hungarian KöMaL magazine, September 2000 issue. You'll find many other challenging problems in English on the KöMaL website.]