Collect as many diamonds as you can by drawing three straight lines.

Can you find a reliable strategy for choosing coordinates that will locate the robber in the minimum number of guesses?

A game for two people, or play online. Given a target number, say 23, and a range of numbers to choose from, say 1-4, players take it in turns to add to the running total to hit their target.

A game in which players take it in turns to choose a number. Can you block your opponent?

Players take it in turns to choose a dot on the grid. The winner is the first to have four dots that can be joined to form a square.

Who said that adding, subtracting, multiplying and dividing couldn't be fun?

Do you know a quick way to check if a number is a multiple of two? How about three, four or six?

How have "Warmsnug" arrived at the prices shown on their windows? Which window has been given an incorrect price?

Four friends must cross a bridge. How can they all cross it in just 17 minutes?

There is nothing half so much worth doing as simply messing about in boats...

Here's a neat trick you can do with an 11 by 11 square...