Each ear of grain would have produced seven hekats of wheat. Greek mathematics produced many classic puzzles. Perhaps the most famous are from Archimedes in his book The Sandreckoner where he gives the Cattle Problem. You can see further details . Archimedes also invented a division of a square into 14 pieces leading to a game similar to Tangrams involving making figures from the 14 pieces.
Tangrams are of Chinese origin and require little mathematical skill.
It is interesting however to see how many convex figures you can make from the 7 tangram pieces. Note again the number 7 which seems to have been associated with magical properties. They were to have a new popularity when Dodgson , writing as Lewis Carroll, introduced Alice type characters. You can see a picture of the Alice tangrams . In fact a wealth of mathematics has arisen from this sequence and today a Journal is devoted to topics related to the sequence.