Find the Robber

map with pins pushed in

A robber is hiding at a crossroads in a modern city, where the roads are all at right angles and equally spaced.

Can you help the police to find him?

Choose coordinates where you think the robber might be hiding. The interactivity tells you the shortest distance to the robber, travelling along the roads.

Try to find the robber using only a few guesses.



Can you guarantee to always find the robber in less than five guesses?

Can you do better than this?

How would your strategy change if the robber were allowed to move 1 block after each guess?

Can you think of any other mathematically interesting variations of the game?




I found it !

Have you found a good strategy for finding the robber?
How many guesses do you need to be sure of finding the robber?

Try (9,9) then (9,3) and see if you can get near from there.

What makes (9,9) and (9,3) good starting points?
Are there better ones?

Starting in the middle of the grid is a good strategy for me.