This cracked me up when I read it. It's from the urban dictionary, one of it's many definitions of evil.
Girls require time and money
(Girls = Time x Money)
But we all know time is money
(Time = Money)
(Girls = Money x Money)
(Money x Money = Money squared)
And beacause money is the root of all evil
(Money = square route of evil)
(Girls = (the square route of evil)squared)
so we are forced to conclude that...
(Girls = Evil)