The formula for the online Deal or No Deal:

 

At the end of each round, find the total of all amounts left on the board less than or equal to 75,000 and then also find the total of all the amounts greater than or equal to 100,000.  The class called these the low sum and the high sum.  The low sum gets multiplied by a factor that changes each round.  It starts at .07 for the first round and then changes to .09 for the 2nd round.  For the 3rd round on up the factors are .13,.17,.2,.25,.33.  For the 8th round on up the factor stays at .5.  My students called this the low total.  The high sum gets multiplied by the exact same factor as the low sum, but then this number gets multiplied by another factor to yield the high total.  (Note:  You could really just use one factor here, but my students noticed that the factors they were calculating were really ugly, and they were multiples of the low sum factors.)  These extra factors are .11, .16,.21,.26,.31.  From here on up this extra factor gets .1 added to it after each successive round.  The amount the dealer offers is the sum of the low and high totals.

 

An example:

 

After round 4, assume that the numbers left on the board are 5,75,5000,25000,50000,75000,200000, and 500000.

 

The low sum = 5 + 75 + 5000 + 25000 + 50000 + 75000 = 155080

The high sum = 200000 + 300000 = 500000

 

low total = 155080 * .17 = 26363.6

high total = 500000 * .17 *.26 = 22100

 

The dealer will offer 26363.6 + 22100 = 48463.6, which in the online version of the game will be rounded to 48464.

 

I hope I explained this well.  I've been working with it (and incorrect variations) for a while now, so I've gotten to know it too well.

 

Kevin Groothuis

Jenison High School