I was hanging out with my friend Matt Onsum on Saturday, and being the math nerd that he is, he shared a couple cool “math magic tricks” with me. Check them out… they aren’t too difficult to figure out but are pretty interesting.

Magic Trick # 1

Three guests check into a hotel. The Cashier says the bill is $30 so each pays $10. Later the cashier realizes the bill should only be $25. To rectify the situation, he gives the bellhop five singles to return to the guests.

On the way back to the room the bellhop’s greed sets in and he decides to give each guest 1 dollar and keep 2 for himself.

So in the end, each guest has paid $9. Three times nine is 27 and the bellhop has $2. Two plus 27 is 29. What happened to the missing dollar?

Magic Trick # 2

If a = b = 1, then:

a = b
a² = ab
a² – b² = ab-b²
(a-b)(a+b) = b(a-b)
a+b = b
2 = 1