Each multiplication puzzle consists of three warships that need to be loaded with ballast so that they are balanced. Unfortunately this is impossible for one of the ships - it will keel over and sink no matter what you do. The other two ships can be loaded with ballast so they are nicely balanced.
Multiplication difficulty ranges from easy (2 x 3 = 6) to hard (13 x 17 = 221).
Problem solving difficulty ranges from easy to open ended.