You will require two sets of cards each card with one of the ten single digits written on them.
Lay down the twenty cards on the table ~ face upwards ~ in a well spread but muddled order.
The task is to remove and keep or discard cards ~ one or two at a time ~ so that the ten different digits remain.
If space is limited use just one set of digits. Pick them up and lay them in a sequence ~ small to large.
Arrange the pile such that quite a few are partly hidden ~ recognizing only parts of shapes makes the task more difficult.
In this case the task is to build individual sequences of 0 to 9. Play could take place in turns ~ or on a take-one-card~each~at-a-time basis ~ or just grab one at a time as quickly as possible. To allow for mis-grabs it is probably best to have one more pack in play over and above the number of players ~ or that could be the adult's set.