for number one the second card must be positive or he would have to put it back if its negative for number 2 the card must be 3 4 5 because negative 2 plus 3 is 1 which is positive and negative 2 plus 4 and 5 would allow her to keep her cards. for the third one danny could have pulled a negaitive 1 2 3 4 and 5. oh dude i forgot to put decimals but still the same thing