65. The Mind-Blowing iPhone Calculator Trick
class: tweener | impressiveness: 5/5 | factors: borrowed phone, can be impromptu or pre-set | requires: iPhone or Android phone | watch full episode
I absolutely love this trick. It’s totally brilliant, completely impromptu, and devilishly clever… so of course I had nothing to do with its creation.
This trick comes to us from the brilliant mind of magician Rich Ferguson… You should check him out at TheIceBreaker.com (it’s okay, I’ll still be here when you get back).
How It Looks: First you write down a prediction. Then ask everyone around you for a string of numbers: birth dates, addresses, dress sizes, anything numeric. All of these numbers are multiplied together using a borrowed phone calculator (you don’t even need to be the one holding the calculator!). Finally, someone presses “equals,” and the final number is displayed. The final number exactly matches your prediction, you are instantly hailed as a national hero, and you go on to an exciting career in politics. Probably.
How it’s Done: This is all based on the fact that while the iPhone calculator looks like a simple “dumb calculator,” it’s actually a powerful, fully-functional scientific calculator. The difference is that simple calculators only perform one function at a time, and they’re performed in the exact order that you type them in. Scientific calculators, however, will follow the proper math order of operations, in which multiplications are always performed before additions.
Here’s how you take advantage of this: before you start the trick, type in whatever number you want to force, plus zero, then hit the times button. Now, no matter what numbers are added to the equation, the expression is:
(your number) + 0 x (any number) x (any number) x (any number) …
Since the calculator follows proper order of operations, the first thing it will do is handle the multiplications, and since anything times 0 is 0, the expression becomes:
(your number) + 0 = (your number)
Watch Demonstration (External link)
If you want to use your own phone for this, just pre-set the first part of the expression and switch to another app. The iPhone will remember what you had already entered. If you want to borrow an iPhone, you should be able to sneakily enter the first part before announcing that you want to try a trick.
In either case, keep in mind that when you begin, the “x” key will be highlighted (since it’s the last one you pressed). To cover this, I make sure to keep the phone in my hand until I start to enter the first digits given. As soon as I start entering numbers, I stop and announce “Oh, crap! I shouldn’t even touch the phone… you guys might think I’m doing something sneaky. Here, you hold it and enter all the numbers in.” The sooner you can get the phone into someone else’s hand, the better.
If you want to be really sneaky, you could borrow someone’s phone earlier in the day and pre-set the number. It’ll sit there like a trap, waiting all day for you to trigger the brain explosion…