אסטרטגיית ניצחון
The number 1234 is written on the board. Two players play a game as follows. On each player's turn, she can subtract a nonzero digit of the number from the number that is on the board, then replacing the old number with the new difference. The winner is the player who hits 0. Which player has a winning strategy? (For example, the first player could subtract 3 from 1234, leaving the number 1231.)
