Algorithms

problem

Vital?

Age

16 to 18

Challenge level

Third challenge cipher
problem

Semicircle

Age

16 to 18

Challenge level

Fourth challenge cipher
problem

Up a Semitone?

Age

16 to 18

Challenge level

Fifth challenge cipher
problem

Ip?

Age

16 to 18

Challenge level

Seventh challenge cipher
problem

A Fine Thing?

Age

16 to 18

Challenge level

Second challenge cipher
problem

Medal Muddle

Age

11 to 14

Challenge level

Countries from across the world competed in a sports tournament. Can you devise an efficient strategy to work out the order in which they finished?
problem

Tis Unique

Age

11 to 14

Challenge level

This addition sum uses all ten digits 0, 1, 2...9 exactly once. Find the sum and show that the one you give is the only possibility.
problem

Skeleton

Age

11 to 14

Challenge level

Can you reconstruct the long division calculation from the 'skeleton'?
problem

Zeller's Birthday

Age

14 to 16

Challenge level

What day of the week were you born on? Do you know? Here's a way to find out.
problem

Peaches in General

Age

14 to 16

Challenge level

It's like 'Peaches Today, Peaches Tomorrow' but interestingly generalized.