It would be useful (especially in 1v1 play), to have a "board" on which you can write information they have about your own numbers;
Example: If they pick "Sum of the 3 left numbers" and get 1, you write on this board "0 0 1", because you know that THEY know you have 0 0 1.
So you know they're only gonna try to get the 4th number, and the color of the last 2.
Which can not only affect your card decisions (perhaps you might want to pick a card just so they don't pick it), but also, sometimes it'll tell you "You need to guess NOW because they solve next turn".
Now, this was just a basic example (you could do this one in your head), but there are complex examples for which this might be useful.
Of course, you could just do that on a sheet of paper or something, but if people are gonna do this, might as well have it in the game!
Example: If they pick "Sum of the 3 left numbers" and get 1, you write on this board "0 0 1", because you know that THEY know you have 0 0 1.
So you know they're only gonna try to get the 4th number, and the color of the last 2.
Which can not only affect your card decisions (perhaps you might want to pick a card just so they don't pick it), but also, sometimes it'll tell you "You need to guess NOW because they solve next turn".
Now, this was just a basic example (you could do this one in your head), but there are complex examples for which this might be useful.
Of course, you could just do that on a sheet of paper or something, but if people are gonna do this, might as well have it in the game!