Taxi Cab Squares (geometry)

Taxi Cab Squares (geometry)

 Taxi Cab Squares  (inspired by the Inscribed square problem of Otto Toeplitz, 1911) Give your students practice with Cartesian coordinates as they explore a new variant of a famous, unsolved problem of Otto Toeplitz (1911). This problem has a very wide spectrum of...
Rainbow Squares

Rainbow Squares

Rainbow Squares is a challenge inspired by Henri Picciotto. Each rainbow arc needs to be anchored at two integers that sum to a square. Here we have tried to find a solution for 1-10, but have failed because the last two numbers, 2 and 3, do not sum to a square. Is...
Using Least 1s

Using Least 1s

Using Least 1s (Conway & Guy, 1962) Using multiplication and addition try to create the target number using the least number of ones.  For example… to get to the number 12, you could do (1+1+1+1)*(1+1+1) or (1+1+1+1+1)*(1+1)+1+1 but the first solution is...
Wormhole!

Wormhole!

Wormhole! (MathPickle, 2011 – Based on work by Harold Coxeter and John Horton Conway) Send your students on a dangerous trip which coincidently happens to be a fantastic introduction/practice for division. If they make a mistake they’ll crash in a heap of...
Klingon Attack

Klingon Attack

  Klingon Attack  The Earth is being attacked by Klingons. It is your job to shoot the enemy spaceships out of the sky using our single ion cannon. Download a pdf of puzzle-sheets here. Much thanks to Ex Astris Scientia for their permission to reprint their...