Maybe it would be fun to come up with some go-themed problems?
Find the smallest natural number N such that the decimal representation of 19*N contains only 9’s.
(if big numbers are a hassle, try the same with 13 instead of 19)
On a perfectly square 19*19 goban, how many pairs of intersections are an integer distance apart?
(e. g. 1-1 and 4-5 are exactly 5 units apart)