Hi RainbowGeek! My great uncle gifted us the same game! We were puzzled at first, but I recently found the original patent application by Iain Sinclair for this style of device. It can be found here:
https://patentimages.storage.googleapis.com/17/c6/b4/d8a2e81f09d160/EP0105620A2.pdf
The pertinent text reads: “The visible markings may be colours, letters, numbers, pictures, or any other characters or devices, preferably arranged on the rotatable members so that lines of the markings can be radially aligned to form a sequence. The object of the puzzle is then to rotate the members until the sequences form the predetermined combinations or patterns. If the markings are numbers the puzzle may be regarded as being solved if each sequence of numbers adds up to the same predetermined amount, or to various predetermined amounts. For example, there may be four members (including the base member) each bearing, at equi-angularly spaced positions, eight numbers, the object being to rotate the members until each radially aligned sequence of numbers adds up to a predetermined number such as 10.”
Therefore, I would suggest that each side of the disc contains two puzzles to solve. Aligning the rings so that each radial adds up to 10, or aligning the rings so that each radial makes a 4-letter word. I genuinely doubt that both can be accomplished simultaneously, although I have not verified this.
I know I’m late to the party on this post! Just wanted to weigh in. =)
Vivian