You’ll find endless options for sliding puzzles these days. Besides, each of them comes with a different level of complexity and design. The point here is that the solvability of the puzzles highly depends on the type of puzzle you buy, keeping in mind your age. For instance, a small kid of 5-6 years will not be able to solve a highly complex number sliding puzzle. It might take a while for them to get the rules straight. But, usually, all the puzzles are solvable.