Box Cars "All Hands On Deck" Mystery Number (adapted)
Missing Addend, Factor
Cards 0-12 (J=11, Q=12, K=0)
Figure out the value of the card on your head
Usually 3 players with one player taking the role of "General". The General says "salute". The other two players take the card from the top of their deck and WITHOUT LOOKING AT IT place it on their forehead so everyone else can see what the card on their forehead is. The General adds the two cards together and says "The sum of your two cards is...." The two players then use the sum and the card they can see on their opponent's forehead to try and figure out their own card.
NOTE: If doing subtraction, be specific as to which card is being subtracted from the other card.
From the Box Cars and One-Eyed Jacks Handouts
https://drive.google.com/file/d/0B_5qnAY1cbT5Yk56a2NxY2cxajg/view