Multi

From BoardGameGeek:

Multiply your fun with Multi, where everything is multiplied! A beautiful combination of mathematical structure and tic tac toe tactics leading to a fantastic 2-player game experience for all ages! Multiple boards, multiple sizes, even play with multiple Xs and Os on the same turn as you play on 10 tic tac toe boards simultaneously! Learn about and apply the structure and symmetry of numbers, multiples, and factors through play! -description from the publisher