In Tribulation, number tiles are laid out in a 7 x 7 grid, similarly to Boggle. Each tile has a number from 1 to 9 on it (the 9 tile is also used as a 6 in some editions). Number disks from 1-50 are shuffled, and one is drawn. Players race to find three tiles whose equation (first times second, plus or minus third, or any other combination of two tiles multiplied and the other added or subtracted) adds to that total. The first to do so wins the disk. Whomever has the most disks when they are all claimed wins the game.
Nominally the game is for 1-6 players, although the upper bound is arbitrary and the rules say nothing about how the game might be played solo. Possible solo challenges involve seeing how many tokens you can claim in a set time (e.g. 10 minutes total) or how many tokens you can claim racing against a countdown timer (e.g. 5-10 seconds per token).