The McGraw Hill 6th grade book series of games.
Instructions:
Find three coins of different sizes (e.g. quarter, nickle, penny). Flip each and record the head/tail value. Look up the x value . Flip the three coins and do a look up in the equation giving you y . Determine the quadrant or axis on which the resulting point should lie . Your opponent may challenge you. Look up the answer in the table on the next page. If you are right and your opponent didn't challenge you, you get a point. If you are right and your opponent did challenge you, you get two points. If you are wrong and your opponent challenged you, your opponent gets a point. If you are wrong and your opponent didn't challenge you, nobody gets a point. Your opponent plays next. 
 vals[0] 
 FindQuadrant 


 Coin tosses (largest to smallest):  TTT TTH THT THH HTT HTH HHT HHH


 x value x = -4 x = -3 x = -2 x = -1 x = 0 x = 1 x = 2 x = 3


 Equation y = 2x + 3 y = 0.5x + -4 y = -1x + 3 y = -3x + 6 y = -7x + 4 y = 5x + -15 y = 13x + -12 y = -4x + 3.3

 
  On a different page so the players have to turn to it...  
 

 vals[0] 
 FindQuadrant 


 Find Quandrant x = -4 x = -3 x = -2 x = -1 x = 0 x = 1 x = 2 x = 3


 y = 2x + 3 lower left lower left lower left upper left upper y-axis upper right upper right upper right


 y = 0.5x + -4 lower left lower left lower left lower left lower y-axis lower right lower right lower right


 y = -1x + 3 upper left upper left upper left upper left upper y-axis upper right upper right right x-axis


 y = -3x + 6 upper left upper left upper left upper left upper y-axis upper right right x-axis lower right


 y = -7x + 4 upper left upper left upper left upper left upper y-axis lower right lower right lower right


 y = 5x + -15 lower left lower left lower left lower left lower y-axis lower right lower right right x-axis


 y = 13x + -12 lower left lower left lower left lower left lower y-axis upper right upper right upper right


 y = -4x + 3.3 upper left upper left upper left upper left upper y-axis lower right lower right lower right