IBM Ponder This #125 · September 2008

Consider a 13x13 checkerboard. It can be partitioned into a collection of smaller square checkerboards in various ways. For example into 169 1x1 checkerboards or into 1 12x12 and 25 1x1 checkerboards. What is the minimum number of smaller square checkerboards that a 13x13 checkerboard can be partitioned into? Show how this can be done. Note we are not asking for (and will not supply) a proof of minimality.

Solution

Best opened after a real attempt

To be added.