Does anyone have the math formula for a "mentalist calculator" type effect. It's the formula usually used with a scientific type calculator wherein you input the equation that allows the spectator to input multiple numbers but the result is always an output that you desire ? The formula reduces the inputs to zero, then adds your target number.

Thanks in advance for any workable formula.

Rather than repeating the simple formula here, I'll just refer you to the episode of Scam School in which it was featured:

Scam School site: http://revision3.com/scamschool/iphonecalculator
YouTube: http://www.youtube.com/watch?v=C7WZ2AAXyFY

Scott,
Thanks a million --- perfect, just what I was searching for!

Another down and dirty way would be to use a spreadsheet on your cell phone.

They enter a 4 digit number in cell B1 then another in cell B2 then another in cell B3 then another in cell B4.

Cell A6 has the words: TOTAL=
Cell B6 has the simple formula: =IF(B4>0,12345," ")

In this example 12345 is your forced total (of course use your own hard coded total).
What the formula in cell B6 is telling the spreadsheet to do is "Before there is any entry in B4 display a blank in cell B6, after something has been entered in B4 then display 12345 in cell B6"

If you have an android based phone then I have found that thinkfreecalc is an excellent free spreadsheet program to download and use. I'm sure that the iphone has several spreadsheet programs available.

Anyone out there with an iphone, what spreadsheet is a good one for the iphone?