1 deck. Average. No redeal.
Concentration Solitaire uses one deck (52 cards). All cards are dealt face down in a row, left to right, one card to a pile.
The object of the game
To remove all the cards, two at a time, in pairs of the same rank.
You may select any two cards by clicking on them to turn them face up. A pair of the same rank will be removed (and $5 will be added to your score), otherwise both cards will be turned back over (and $1 will be subtracted from your score).