The idea is to rotate them until there is a correct equation on all 4 sides of the 7 blocks. The equation is read from left to right, regardless of operation priority. The blocks stay as a string but will rotate individually. There are 1024 possible permutations of the blocks, but only ONE correct solution.
There is a 7 block model (here) and also a more difficult 9 block model offered on a different listing. They are high quality all wood construction with deeply burned laser engraved numbers.
Difficulty: Level 3 of 5
Made by Creative Crafthouse, Hudson, FL