Sum Fun

Description

How it works: There are four square tiles with single digits on each corner and a square frame with numbers around its perimeter.  A player would pick up one of the tiles, rotate it, and place it into the frame so that the numbers in the corner of the frame combined with the number on the tile add up to 10.

The player would then select a second tile and, after rotating as needed, place it into the frame, again placing it such that the numbers wherever four digits come together add up to 10.  This would continue until all four squares are placed and all sums are confirmed to be 10.

There are numbers on both sides of each tile, raised on one side, and recessed on the other.  For there to be a valid solution, the puzzle requires that the tiles are turned such that all numbers are the same configuration (raised or recessed).  Once a solution has been found for one configuration, all four tiles may be turned over for a new challenge.

Story behind the puzzle: This one has been in my collection for several years, but in a 3×3 arrangement, meaning there are nine tiles to place.  When considering which of my puzzles were suitable for elementary age children, I realized a 2×2 arrangement would be just right.  The 3×3 option is available as Sum More Fun on this site.